diff --git a/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt b/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt
index fb620fd2b2d..4738c233906 100644
--- a/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt
@@ -212,19 +212,23 @@ class KotlinEvaluator(val codeFragment: JetCodeFragment,
             ClassReader(compiledData.bytecodes).accept(object : ClassVisitor(ASM5) {
                 override fun visitMethod(access: Int, name: String, desc: String, signature: String?, exceptions: Array<out String>?): MethodVisitor? {
                     if (name == compiledData.funName) {
-                        val args = context.getArgumentsForEval4j(compiledData.parameters.getParameterNames(), Type.getArgumentTypes(desc))
+                        val argumentTypes = Type.getArgumentTypes(desc)
+                        val args = context.getArgumentsForEval4j(compiledData.parameters.getParameterNames(), argumentTypes)
+
                         return object : MethodNode(Opcodes.ASM5, access, name, desc, signature, exceptions) {
                             override fun visitEnd() {
                                 val breakpoints = virtualMachine.eventRequestManager().breakpointRequests()
                                 breakpoints?.forEach { it.disable() }
 
+                                val eval = JDIEval(virtualMachine,
+                                                   context.getClassLoader(),
+                                                   context.getSuspendContext().getThread()?.getThreadReference()!!,
+                                                   context.getSuspendContext().getInvokePolicy())
+
                                 resultValue = interpreterLoop(
                                         this,
-                                        makeInitialFrame(this, args),
-                                        JDIEval(virtualMachine,
-                                                context.getClassLoader(),
-                                                context.getSuspendContext().getThread()?.getThreadReference()!!,
-                                                context.getSuspendContext().getInvokePolicy())
+                                        makeInitialFrame(this, args.zip(argumentTypes).map { boxOrUnboxArgumentIfNeeded(eval, it.first, it.second) }),
+                                        eval
                                 )
 
                                 breakpoints?.forEach { it.enable() }
@@ -239,6 +243,29 @@ class KotlinEvaluator(val codeFragment: JetCodeFragment,
             return resultValue ?: throw IllegalStateException("resultValue is null: cannot find method ${compiledData.funName}")
         }
 
+        private fun boxOrUnboxArgumentIfNeeded(eval: JDIEval, argumentValue: Value, parameterType: Type): Value {
+            val argumentType = argumentValue.asmType
+
+            if (AsmUtil.isPrimitive(parameterType) && !AsmUtil.isPrimitive(argumentType)) {
+                try {
+                    val unboxedType = AsmUtil.unboxType(argumentType)
+                    if (parameterType == unboxedType) {
+                        return eval.unboxType(argumentValue, parameterType)
+                    }
+                }
+                catch(ignored: UnsupportedOperationException) {
+                }
+            }
+
+            if (!AsmUtil.isPrimitive(parameterType) && AsmUtil.isPrimitive(argumentType)) {
+                if (parameterType == AsmUtil.boxType(argumentType)) {
+                    return eval.boxType(argumentValue)
+                }
+            }
+
+            return argumentValue
+        }
+
         private fun InterpreterResult.toJdiValue(vm: VirtualMachine): com.sun.jdi.Value? {
             val jdiValue = when (this) {
                 is ValueReturned -> result
diff --git a/idea/testData/debugger/tinyApp/outs/boxParam.out b/idea/testData/debugger/tinyApp/outs/boxParam.out
new file mode 100644
index 00000000000..1e3be21eabf
--- /dev/null
+++ b/idea/testData/debugger/tinyApp/outs/boxParam.out
@@ -0,0 +1,9 @@
+LineBreakpoint created at boxParam.kt:13
+!JDK_HOME!\bin\java -agentlib:jdwp=transport=dt_socket,address=!HOST_NAME!:!HOST_PORT!,suspend=y,server=n -Dfile.encoding=!FILE_ENCODING! -classpath !APP_PATH!\classes;!KOTLIN_RUNTIME!;!CUSTOM_LIBRARY!;!RT_JAR! boxParam.BoxParamPackage
+Connected to the target VM, address: '!HOST_NAME!:PORT_NAME!', transport: 'socket'
+boxParam.kt:13
+Compile bytecode for nullableInt?.plus(1)
+Compile bytecode for nullableByte?.plus(1)
+Disconnected from the target VM, address: '!HOST_NAME!:PORT_NAME!', transport: 'socket'
+
+Process finished with exit code 0
diff --git a/idea/testData/debugger/tinyApp/outs/unboxParam.out b/idea/testData/debugger/tinyApp/outs/unboxParam.out
new file mode 100644
index 00000000000..afecd718b84
--- /dev/null
+++ b/idea/testData/debugger/tinyApp/outs/unboxParam.out
@@ -0,0 +1,8 @@
+LineBreakpoint created at unboxParam.kt:12
+!JDK_HOME!\bin\java -agentlib:jdwp=transport=dt_socket,address=!HOST_NAME!:!HOST_PORT!,suspend=y,server=n -Dfile.encoding=!FILE_ENCODING! -classpath !APP_PATH!\classes;!KOTLIN_RUNTIME!;!CUSTOM_LIBRARY!;!RT_JAR! unboxParam.UnboxParamPackage
+Connected to the target VM, address: '!HOST_NAME!:PORT_NAME!', transport: 'socket'
+unboxParam.kt:12
+Compile bytecode for fooInt(nullableInt)
+Disconnected from the target VM, address: '!HOST_NAME!:PORT_NAME!', transport: 'socket'
+
+Process finished with exit code 0
diff --git a/idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/boxParam.kt b/idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/boxParam.kt
new file mode 100644
index 00000000000..ff8c9d01706
--- /dev/null
+++ b/idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/boxParam.kt
@@ -0,0 +1,14 @@
+package boxParam
+
+fun main(args: Array<String>) {
+    val nullableInt: Int? = 1
+    val nullableByte: Byte? = 1
+
+    // EXPRESSION: nullableInt?.plus(1)
+    // RESULT: instance of java.lang.Integer(id=ID): Ljava/lang/Integer;
+
+    // EXPRESSION: nullableByte?.plus(1)
+    // RESULT: instance of java.lang.Integer(id=ID): Ljava/lang/Integer;
+    //Breakpoint!
+    val i = 1
+}
\ No newline at end of file
diff --git a/idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/unboxParam.kt b/idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/unboxParam.kt
new file mode 100644
index 00000000000..cccc30ae8ff
--- /dev/null
+++ b/idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/unboxParam.kt
@@ -0,0 +1,17 @@
+package unboxParam
+
+fun main(args: Array<String>) {
+    val nullableInt = fooNullableInt()
+    if (nullableInt == null) {
+        return
+    }
+
+    // EXPRESSION: fooInt(nullableInt)
+    // RESULT: 1: I
+    //Breakpoint!
+    val a = fooInt(nullableInt)
+}
+
+fun fooNullableInt(): Int? = 1
+
+fun fooInt(param: Int) = param
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluateExpressionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluateExpressionTestGenerated.java
index 2e0fbd714c7..cebba7a2719 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluateExpressionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluateExpressionTestGenerated.java
@@ -55,6 +55,12 @@ public class KotlinEvaluateExpressionTestGenerated extends AbstractKotlinEvaluat
             doSingleBreakpointTest(fileName);
         }
 
+        @TestMetadata("boxParam.kt")
+        public void testBoxParam() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/boxParam.kt");
+            doSingleBreakpointTest(fileName);
+        }
+
         @TestMetadata("callableBug.kt")
         public void testCallableBug() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/callableBug.kt");
@@ -217,6 +223,12 @@ public class KotlinEvaluateExpressionTestGenerated extends AbstractKotlinEvaluat
             doSingleBreakpointTest(fileName);
         }
 
+        @TestMetadata("unboxParam.kt")
+        public void testUnboxParam() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/unboxParam.kt");
+            doSingleBreakpointTest(fileName);
+        }
+
         @TestMetadata("unsafeCall.kt")
         public void testUnsafeCall() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/unsafeCall.kt");