diff --git a/ChangeLog.md b/ChangeLog.md
index b8ed1700881..dc42df04187 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -42,6 +42,7 @@ Issues fixed:
 - [KT-11512](https://youtrack.jetbrains.com/issue/KT-11512) Allow choosing any source root in "Move file to directory" intention
 - [KT-10950](https://youtrack.jetbrains.com/issue/KT-10950) Keep original file package name when moving top-level declarations to separate file (provided it's not ambiguous)
 - [KT-10174](https://youtrack.jetbrains.com/issue/KT-10174) Optimize imports after applying "Move declaration to separate file" intention
+- [KT-12035](https://youtrack.jetbrains.com/issue/KT-12035) Auto-format cast expressions
 
 #### Debugger
 
diff --git a/idea/formatter/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt b/idea/formatter/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt
index 2133bc10edc..38704c29a19 100644
--- a/idea/formatter/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt
+++ b/idea/formatter/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt
@@ -164,6 +164,8 @@ fun createSpacingBuilder(settings: CodeStyleSettings, builderUtil: KotlinSpacing
             betweenInside(DOT, IDENTIFIER, FUN).spacing(0, 0, 0, false, 0)
             afterInside(IDENTIFIER, FUN).spacing(0, 0, 0, false, 0)
 
+            around(AS_KEYWORD).spaces(1)
+
             // before LPAR in constructor(): this() {}
             after(CONSTRUCTOR_DELEGATION_REFERENCE).spacing(0, 0, 0, false, 0)
 
diff --git a/idea/testData/formatter/Cast.after.kt b/idea/testData/formatter/Cast.after.kt
new file mode 100644
index 00000000000..542750af173
--- /dev/null
+++ b/idea/testData/formatter/Cast.after.kt
@@ -0,0 +1,3 @@
+fun foo() {
+    val a = 1 as Int
+}
\ No newline at end of file
diff --git a/idea/testData/formatter/Cast.kt b/idea/testData/formatter/Cast.kt
new file mode 100644
index 00000000000..ce6776f3708
--- /dev/null
+++ b/idea/testData/formatter/Cast.kt
@@ -0,0 +1,3 @@
+fun foo() {
+    val a = 1  as  Int
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java b/idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java
index f0ab1d2874a..462325de902 100644
--- a/idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java
@@ -91,6 +91,12 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             doTest(fileName);
         }
 
+        @TestMetadata("Cast.after.kt")
+        public void testCast() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/Cast.after.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("CatchFinallyOnNewLine.after.kt")
         public void testCatchFinallyOnNewLine() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/CatchFinallyOnNewLine.after.kt");