diff --git a/shadow/shadow_test.go b/shadow/shadow_test.go
index 9790d5a1..40302f20 100644
--- a/shadow/shadow_test.go
+++ b/shadow/shadow_test.go
@@ -366,12 +366,12 @@ func TestGet(t *testing.T) {
 		},
 		"Error": {
 			response: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 			responseTopic: "get/rejected",
 			err: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 		},
@@ -460,12 +460,12 @@ func TestDesire(t *testing.T) {
 		"Error": {
 			input: map[string]interface{}{"key": "value"},
 			response: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 			responseTopic: "update/rejected",
 			err: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 		},
@@ -554,12 +554,12 @@ func TestReport(t *testing.T) {
 		"Error": {
 			input: map[string]interface{}{"key": "value"},
 			response: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 			responseTopic: "update/rejected",
 			err: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 		},
@@ -631,12 +631,12 @@ func TestDelete(t *testing.T) {
 		},
 		"Error": {
 			response: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 			responseTopic: "delete/rejected",
 			err: &ErrorResponse{
-				Code:    "Failed",
+				Code:    400,
 				Message: "Reason",
 			},
 		},
diff --git a/shadow/state.go b/shadow/state.go
index e2e21afb..ee3db8eb 100644
--- a/shadow/state.go
+++ b/shadow/state.go
@@ -15,7 +15,7 @@ type simpleRequest struct {
 
 // ErrorResponse represents error response from AWS IoT.
 type ErrorResponse struct {
-	Code        string `json:"code"`
+	Code        int    `json:"code"`
 	Message     string `json:"message"`
 	Timestamp   int64  `json:"timestamp"`
 	ClientToken string `json:"clientToken"`
@@ -23,7 +23,7 @@ type ErrorResponse struct {
 
 // Error implements error interface.
 func (e *ErrorResponse) Error() string {
-	return fmt.Sprintf("%s (%s): %s", e.Code, e.ClientToken, e.Message)
+	return fmt.Sprintf("%d (%s): %s", e.Code, e.ClientToken, e.Message)
 }
 
 // ThingState represents Thing Shadow State.
diff --git a/shadow/state_test.go b/shadow/state_test.go
index 722efea7..5a8152e0 100644
--- a/shadow/state_test.go
+++ b/shadow/state_test.go
@@ -3,6 +3,7 @@ package shadow
 import (
 	"encoding/json"
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -73,3 +74,17 @@ func TestThingDocument_update(t *testing.T) {
 		)
 	}
 }
+
+func TestErrorResponse(t *testing.T) {
+	err := &ErrorResponse{
+		Code:    100,
+		Message: "error message",
+	}
+	errStr := err.Error()
+	if !strings.Contains(errStr, "100") {
+		t.Error("Error string should contain error code")
+	}
+	if !strings.Contains(errStr, "error message") {
+		t.Error("Error string should contain error message")
+	}
+}