diff --git a/CHANGES b/CHANGES
index 9533ad0..c24c2b2 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,7 +1,8 @@
 Apache Thrift Changelog
 
 Breaking Changes since 0.11.0 [for 0.12.0]:
--------------------------------------------------------------------------------- 
+--------------------------------------------------------------------------------
+    * [THRIFT-4529] - Rust enum variants are now camel-cased instead of uppercased to conform to Rust naming conventions
     * [THRIFT-4448] - Support for golang 1.6 and earlier has been dropped.
     * [THRIFT-4474] - PHP now uses the PSR-4 loader by default instead of class maps.
     * [THRIFT-4532] - method signatures changed in the compiler's t_oop_generator.
diff --git a/compiler/cpp/src/thrift/generate/t_rs_generator.cc b/compiler/cpp/src/thrift/generate/t_rs_generator.cc
index a01c626..fed1a66 100644
--- a/compiler/cpp/src/thrift/generate/t_rs_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_rs_generator.cc
@@ -502,6 +502,9 @@
   // the server half of a Thrift service.
   string rust_sync_processor_impl_name(t_service *tservice);
 
+  // Return the variant name for an enum variant
+  string rust_enum_variant_name(const string& name);
+
   // Properly uppercase names for use in Rust.
   string rust_upper_case(const string& name);
 
@@ -883,7 +886,7 @@
     render_rustdoc((t_doc*) val);
     f_gen_
       << indent()
-      << uppercase(val->get_name())
+      << rust_enum_variant_name(val->get_name())
       << " = "
       << val->get_value()
       << ","
@@ -944,7 +947,7 @@
     f_gen_
       << indent()
       << val->get_value()
-      << " => Ok(" << enum_name << "::" << uppercase(val->get_name()) << "),"
+      << " => Ok(" << enum_name << "::" << rust_enum_variant_name(val->get_name()) << "),"
       << endl;
   }
   f_gen_ << indent() << "_ => {" << endl;
@@ -3279,6 +3282,23 @@
   return "T" + rust_camel_case(tservice->get_name()) + "ProcessFunctions";
 }
 
+string t_rs_generator::rust_enum_variant_name(const string &name) {
+  bool all_uppercase = true;
+
+  for (size_t i = 0; i < name.size(); i++) {
+    if (isalnum(name[i]) && islower(name[i])) {
+      all_uppercase = false;
+      break;
+    }
+  }
+
+  if (all_uppercase) {
+    return capitalize(camelcase(lowercase(name)));
+  } else {
+    return capitalize(camelcase(name));
+  }
+}
+
 string t_rs_generator::rust_upper_case(const string& name) {
   string str(uppercase(underscore(name)));
   string_replace(str, "__", "_");
diff --git a/lib/rs/README.md b/lib/rs/README.md
index 8b35eda..7c37a10 100644
--- a/lib/rs/README.md
+++ b/lib/rs/README.md
@@ -37,6 +37,57 @@
 
 Full [Rustdoc](https://docs.rs/thrift/)
 
+## Compatibility
+
+The Rust library and auto-generated code targets Rust versions 1.28+.
+It does not currently use any Rust 2018 features.
+
+### Breaking Changes
+
+Breaking changes are minimized. When they are made they will be outlined below with transition guidelines.
+
+##### Thrift 0.12.0
+
+* **[THRIFT-4529]** - Rust enum variants are now camel-cased instead of uppercased to conform to Rust naming conventions
+
+    Previously, enum variants were uppercased in the auto-generated code.
+    For example, the following thrift enum:
+
+    ```thrift
+    // THRIFT
+    enum Operation {
+      ADD,
+      SUBTRACT,
+      MULTIPLY,
+      DIVIDE,
+    }
+    ```
+    
+    used to generate:
+    
+    ```rust
+    // OLD AUTO-GENERATED RUST
+    pub enum Operation {
+       ADD,
+       SUBTRACT,
+       MULTIPLY,
+       DIVIDE,
+     }
+    ```
+    It *now* generates:
+    ```rust
+    // NEW AUTO-GENERATED RUST
+    pub enum Operation {
+       Add,
+       Subtract,
+       Multiply,
+       Divide,
+     }
+    ```
+    
+    You will have to change all enum variants in your code to use camel-cased names.
+    This should be a search and replace.
+
 ## Contributing
 
 Bug reports and PRs are always welcome! Please see the
diff --git a/lib/rs/test/src/bin/kitchen_sink_server.rs b/lib/rs/test/src/bin/kitchen_sink_server.rs
index ae70262..e2c4a27 100644
--- a/lib/rs/test/src/bin/kitchen_sink_server.rs
+++ b/lib/rs/test/src/bin/kitchen_sink_server.rs
@@ -17,23 +17,23 @@
 
 #[macro_use]
 extern crate clap;
-
 extern crate kitchen_sink;
 extern crate thrift;
 
+use thrift::protocol::{TBinaryInputProtocolFactory, TBinaryOutputProtocolFactory,
+                       TCompactInputProtocolFactory, TCompactOutputProtocolFactory,
+                       TInputProtocolFactory, TOutputProtocolFactory};
+use thrift::server::TServer;
+use thrift::transport::{TFramedReadTransportFactory, TFramedWriteTransportFactory,
+                        TReadTransportFactory, TWriteTransportFactory};
+
 use kitchen_sink::base_one::Noodle;
 use kitchen_sink::base_two::{BrothType, Napkin, NapkinServiceSyncHandler, Ramen, RamenServiceSyncHandler};
-use kitchen_sink::midlayer::{Dessert, Meal, MealServiceSyncHandler, MealServiceSyncProcessor};
+use kitchen_sink::midlayer::{Dessert, Meal, MealServiceSyncHandler, MealServiceSyncProcessor, Pie};
 use kitchen_sink::recursive;
 use kitchen_sink::ultimate::{Drink, FullMeal, FullMealAndDrinks,
                              FullMealAndDrinksServiceSyncProcessor, FullMealServiceSyncHandler};
 use kitchen_sink::ultimate::FullMealAndDrinksServiceSyncHandler;
-use thrift::protocol::{TBinaryInputProtocolFactory, TBinaryOutputProtocolFactory,
-                       TCompactInputProtocolFactory, TCompactOutputProtocolFactory,
-                       TInputProtocolFactory, TOutputProtocolFactory};
-use thrift::transport::{TFramedReadTransportFactory, TFramedWriteTransportFactory,
-                        TReadTransportFactory, TWriteTransportFactory};
-use thrift::server::TServer;
 
 fn main() {
     match run() {
@@ -207,7 +207,13 @@
 
 impl FullMealAndDrinksServiceSyncHandler for FullHandler {
     fn handle_full_meal_and_drinks(&self) -> thrift::Result<FullMealAndDrinks> {
-        Ok(FullMealAndDrinks::new(full_meal(), Drink::WHISKEY))
+        println!("full_meal_and_drinks: handling full meal and drinks call");
+        Ok(FullMealAndDrinks::new(full_meal(), Drink::CanadianWhisky))
+    }
+
+    fn handle_best_pie(&self) -> thrift::Result<Pie> {
+        println!("full_meal_and_drinks: handling pie call");
+        Ok(Pie::MississippiMud) // I prefer Pie::Pumpkin, but I have to check that casing works
     }
 }
 
@@ -252,7 +258,7 @@
 }
 
 fn ramen() -> Ramen {
-    Ramen::new("Mr Ramen".to_owned(), 72, BrothType::MISO)
+    Ramen::new("Mr Ramen".to_owned(), 72, BrothType::Miso)
 }
 
 fn napkin() -> Napkin {
diff --git a/lib/rs/test/thrifts/Midlayer.thrift b/lib/rs/test/thrifts/Midlayer.thrift
index cf1157c..16ff49b 100644
--- a/lib/rs/test/thrifts/Midlayer.thrift
+++ b/lib/rs/test/thrifts/Midlayer.thrift
@@ -46,6 +46,15 @@
   [6, 7, 8]
 ]
 
+enum Pie {
+  PUMPKIN,
+  apple, // intentionally poorly cased
+  STRAWBERRY_RHUBARB,
+  Key_Lime, // intentionally poorly cased
+  coconut_Cream, // intentionally poorly cased
+  mississippi_mud, // intentionally poorly cased
+}
+
 struct Meal {
   1: Base_One.Noodle noodle
   2: Base_Two.Ramen ramen
diff --git a/lib/rs/test/thrifts/Ultimate.thrift b/lib/rs/test/thrifts/Ultimate.thrift
index 8154d91..72fa100 100644
--- a/lib/rs/test/thrifts/Ultimate.thrift
+++ b/lib/rs/test/thrifts/Ultimate.thrift
@@ -27,6 +27,21 @@
   WATER,
   WHISKEY,
   WINE,
+  scotch, // intentionally poorly cased
+  LATE_HARVEST_WINE,
+  India_Pale_Ale, // intentionally poorly cased
+  apple_cider, // intentially poorly cased
+  belgian_Ale, // intentionally poorly cased
+  Canadian_whisky, // intentionally poorly cased
+}
+
+const map<i8, Midlayer.Pie> RankedPies = {
+  1: Midlayer.Pie.PUMPKIN,
+  2: Midlayer.Pie.STRAWBERRY_RHUBARB,
+  3: Midlayer.Pie.apple,
+  4: Midlayer.Pie.mississippi_mud,
+  5: Midlayer.Pie.coconut_Cream,
+  6: Midlayer.Pie.Key_Lime,
 }
 
 struct FullMeal {
@@ -45,5 +60,7 @@
 
 service FullMealAndDrinksService extends FullMealService {
   FullMealAndDrinks fullMealAndDrinks()
+
+  Midlayer.Pie bestPie()
 }
 
diff --git a/test/rs/src/bin/test_client.rs b/test/rs/src/bin/test_client.rs
index 297faf9..29b5b88 100644
--- a/test/rs/src/bin/test_client.rs
+++ b/test/rs/src/bin/test_client.rs
@@ -216,7 +216,7 @@
 
     info!("testEnum");
     {
-        verify_expected_result(thrift_test_client.test_enum(Numberz::TWO), Numberz::TWO)?;
+        verify_expected_result(thrift_test_client.test_enum(Numberz::Two), Numberz::Two)?;
     }
 
     info!("testBinary");
@@ -391,7 +391,7 @@
         };
 
         verify_expected_result(
-            thrift_test_client.test_multi(1, -123948, -19234123981, m_snd, Numberz::EIGHT, 81),
+            thrift_test_client.test_multi(1, -123948, -19234123981, m_snd, Numberz::Eight, 81),
             s_cmp,
         )?;
     }
@@ -405,8 +405,8 @@
     // }
     {
         let mut arg_map_usermap: BTreeMap<Numberz, i64> = BTreeMap::new();
-        arg_map_usermap.insert(Numberz::ONE, 4289);
-        arg_map_usermap.insert(Numberz::EIGHT, 19);
+        arg_map_usermap.insert(Numberz::One, 4289);
+        arg_map_usermap.insert(Numberz::Eight, 19);
 
         let mut arg_vec_xtructs: Vec<Xtruct> = Vec::new();
         arg_vec_xtructs.push(
@@ -439,15 +439,15 @@
             user_map: Some(arg_map_usermap),
             xtructs: Some(arg_vec_xtructs),
         };
-        s_cmp_nested_1.insert(Numberz::TWO, insanity.clone());
-        s_cmp_nested_1.insert(Numberz::THREE, insanity.clone());
+        s_cmp_nested_1.insert(Numberz::Two, insanity.clone());
+        s_cmp_nested_1.insert(Numberz::Three, insanity.clone());
 
         let mut s_cmp_nested_2: BTreeMap<Numberz, Insanity> = BTreeMap::new();
         let empty_insanity = Insanity {
             user_map: Some(BTreeMap::new()),
             xtructs: Some(Vec::new()),
         };
-        s_cmp_nested_2.insert(Numberz::SIX, empty_insanity);
+        s_cmp_nested_2.insert(Numberz::Six, empty_insanity);
 
         let mut s_cmp: BTreeMap<UserId, BTreeMap<Numberz, Insanity>> = BTreeMap::new();
         s_cmp.insert(1 as UserId, s_cmp_nested_1);
diff --git a/test/rs/src/bin/test_server.rs b/test/rs/src/bin/test_server.rs
index 1976bf4..81c1ec7 100644
--- a/test/rs/src/bin/test_server.rs
+++ b/test/rs/src/bin/test_server.rs
@@ -273,15 +273,15 @@
     ) -> thrift::Result<BTreeMap<UserId, BTreeMap<Numberz, Insanity>>> {
         info!("testInsanity({:?})", argument);
         let mut map_0: BTreeMap<Numberz, Insanity> = BTreeMap::new();
-        map_0.insert(Numberz::TWO, argument.clone());
-        map_0.insert(Numberz::THREE, argument.clone());
+        map_0.insert(Numberz::Two, argument.clone());
+        map_0.insert(Numberz::Three, argument.clone());
 
         let mut map_1: BTreeMap<Numberz, Insanity> = BTreeMap::new();
         let insanity = Insanity {
             user_map: None,
             xtructs: None,
         };
-        map_1.insert(Numberz::SIX, insanity);
+        map_1.insert(Numberz::Six, insanity);
 
         let mut ret: BTreeMap<UserId, BTreeMap<Numberz, Insanity>> = BTreeMap::new();
         ret.insert(1, map_0);
diff --git a/tutorial/rs/src/bin/tutorial_client.rs b/tutorial/rs/src/bin/tutorial_client.rs
index 24ab4be..e7192b6 100644
--- a/tutorial/rs/src/bin/tutorial_client.rs
+++ b/tutorial/rs/src/bin/tutorial_client.rs
@@ -71,7 +71,7 @@
 
     // let's do...a multiply!
     let res = client
-        .calculate(logid, Work::new(7, 8, Operation::MULTIPLY, None))?;
+        .calculate(logid, Work::new(7, 8, Operation::Multiply, None))?;
     println!("multiplied 7 and 8 and got {}", res);
 
     // let's get the log for it
@@ -81,7 +81,7 @@
     // ok - let's be bad :(
     // do a divide by 0
     // logid doesn't matter; won't be recorded
-    let res = client.calculate(77, Work::new(2, 0, Operation::DIVIDE, "we bad".to_owned()));
+    let res = client.calculate(77, Work::new(2, 0, Operation::Divide, "we bad".to_owned()));
 
     // we should have gotten an exception back
     match res {
diff --git a/tutorial/rs/src/bin/tutorial_server.rs b/tutorial/rs/src/bin/tutorial_server.rs
index 8db8eed..171c4ce 100644
--- a/tutorial/rs/src/bin/tutorial_server.rs
+++ b/tutorial/rs/src/bin/tutorial_server.rs
@@ -134,10 +134,10 @@
                 let num2 = w.num2.as_ref().expect("operands checked");
 
                 match *op {
-                    Operation::ADD => Ok(num1 + num2),
-                    Operation::SUBTRACT => Ok(num1 - num2),
-                    Operation::MULTIPLY => Ok(num1 * num2),
-                    Operation::DIVIDE => {
+                    Operation::Add => Ok(num1 + num2),
+                    Operation::Subtract => Ok(num1 - num2),
+                    Operation::Multiply => Ok(num1 * num2),
+                    Operation::Divide => {
                         if *num2 == 0 {
                             Err(
                                 InvalidOperation {