diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerForEnumsGenerator.kt b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerForEnumsGenerator.kt
index 054b752915b..ccfcd93a394 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerForEnumsGenerator.kt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerForEnumsGenerator.kt
@@ -76,6 +76,7 @@ class SerializerForEnumsGenerator(
         return irInvoke(
             null, ctor,
             irString(serialName),
+            irInt(serializableDescriptor.enumEntries().size),
             typeHint = ctor.descriptor.returnType.toIrType()
         )
     }
diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerIrGenerator.kt b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerIrGenerator.kt
index 6002aa69cb3..69929e2be98 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerIrGenerator.kt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerIrGenerator.kt
@@ -110,7 +110,7 @@ open class SerializerIrGenerator(val irClass: IrClass, final override val compil
         val serialClassDescImplCtor = compilerContext.symbolTable.referenceConstructor(serialDescImplConstructor)
         return irInvoke(
             null, serialClassDescImplCtor,
-            irString(serialName), if (isGeneratedSerializer) correctThis else irNull()
+            irString(serialName), if (isGeneratedSerializer) correctThis else irNull(), irInt(serializableProperties.size)
         )
     }
 
diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerForEnumsTranslator.kt b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerForEnumsTranslator.kt
index 18c9df30325..58af96c4108 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerForEnumsTranslator.kt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerForEnumsTranslator.kt
@@ -53,7 +53,7 @@ class SerializerForEnumsTranslator(
         val ctor = serialDescForEnums.unsubstitutedPrimaryConstructor!!
         return JsNew(
             context.getInnerReference(ctor),
-            listOf(JsStringLiteral(serialName))
+            listOf(JsStringLiteral(serialName), JsIntLiteral(serializableDescriptor.enumEntries().size))
         )
     }
 
diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerJsTranslator.kt b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerJsTranslator.kt
index 6442a8c7b00..b58942b8afa 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerJsTranslator.kt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerJsTranslator.kt
@@ -83,7 +83,7 @@ open class SerializerJsTranslator(
         val serialDescImplConstructor = baseSerialDescImplClass.unsubstitutedPrimaryConstructor!!
         return JsNew(
             context.getInnerReference(serialDescImplConstructor),
-            listOf(JsStringLiteral(serialName), if (isGeneratedSerializer) correctThis else JsNullLiteral())
+            listOf(JsStringLiteral(serialName), if (isGeneratedSerializer) correctThis else JsNullLiteral(), JsIntLiteral(serializableProperties.size))
         )
     }
 
diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerCodegenImpl.kt b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerCodegenImpl.kt
index 56f966a8d65..353e0c4b290 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerCodegenImpl.kt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerCodegenImpl.kt
@@ -110,7 +110,8 @@ open class SerializerCodegenImpl(
         } else {
             load(0, serializerAsmType)
         }
-        invokespecial(descImplType.internalName, "<init>", "(Ljava/lang/String;${generatedSerializerType.descriptor})V", false)
+        aconst(serializableProperties.size)
+        invokespecial(descImplType.internalName, "<init>", "(Ljava/lang/String;${generatedSerializerType.descriptor}I)V", false)
     }
 
     protected open fun ExpressionCodegen.addElementsContentToDescriptor(descriptorVar: Int) = with(v) {
diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerForEnumsCodegen.kt b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerForEnumsCodegen.kt
index 3dff6372cab..04af0fa80ed 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerForEnumsCodegen.kt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerForEnumsCodegen.kt
@@ -46,7 +46,8 @@ class SerializerForEnumsCodegen(
         anew(descriptorForEnumsType)
         dup()
         aconst(serialName)
-        invokespecial(descriptorForEnumsType.internalName, "<init>", "(Ljava/lang/String;)V", false)
+        aconst(serializableDescriptor.enumEntries().size)
+        invokespecial(descriptorForEnumsType.internalName, "<init>", "(Ljava/lang/String;I)V", false)
         checkcast(descImplType)
     }
 
diff --git a/plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.txt b/plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.txt
index 3ab0a27403b..48aad25beb7 100644
--- a/plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.txt
+++ b/plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.txt
@@ -17,7 +17,8 @@ public final class ListOfUsers$$serializer : java/lang/Object, kotlinx/serializa
           LDC (ListOfUsers)
           GETSTATIC (INSTANCE, LListOfUsers$$serializer;)
           CHECKCAST
-          INVOKESPECIAL (kotlinx/serialization/internal/SerialClassDescImpl, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;)V)
+          LDC (1)
+          INVOKESPECIAL (kotlinx/serialization/internal/SerialClassDescImpl, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;I)V)
           ASTORE (0)
           ALOAD (0)
           LDC (list)
@@ -317,7 +318,8 @@ public final class OptionalUser$$serializer : java/lang/Object, kotlinx/serializ
           LDC (OptionalUser)
           GETSTATIC (INSTANCE, LOptionalUser$$serializer;)
           CHECKCAST
-          INVOKESPECIAL (kotlinx/serialization/internal/SerialClassDescImpl, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;)V)
+          LDC (1)
+          INVOKESPECIAL (kotlinx/serialization/internal/SerialClassDescImpl, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;I)V)
           ASTORE (0)
           ALOAD (0)
           LDC (user)
@@ -659,7 +661,8 @@ public final class User$$serializer : java/lang/Object, kotlinx/serialization/in
           LDC (User)
           GETSTATIC (INSTANCE, LUser$$serializer;)
           CHECKCAST
-          INVOKESPECIAL (kotlinx/serialization/internal/SerialClassDescImpl, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;)V)
+          LDC (2)
+          INVOKESPECIAL (kotlinx/serialization/internal/SerialClassDescImpl, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;I)V)
           ASTORE (0)
           ALOAD (0)
           LDC (firstName)