diff --git a/builtin/providers/aws/resource_aws_cloudwatch_event_rule.go b/builtin/providers/aws/resource_aws_cloudwatch_event_rule.go
index 3181b8480..0aff703f7 100644
--- a/builtin/providers/aws/resource_aws_cloudwatch_event_rule.go
+++ b/builtin/providers/aws/resource_aws_cloudwatch_event_rule.go
@@ -39,8 +39,11 @@ func resourceAwsCloudWatchEventRule() *schema.Resource {
 			"event_pattern": &schema.Schema{
 				Type:         schema.TypeString,
 				Optional:     true,
-				ValidateFunc: validateMaxLength(2048),
-				StateFunc:    normalizeJson,
+				ValidateFunc: validateEventPatternValue(2048),
+				StateFunc: func(v interface{}) string {
+					json, _ := normalizeJsonString(v)
+					return json
+				},
 			},
 			"description": &schema.Schema{
 				Type:         schema.TypeString,
@@ -123,7 +126,8 @@ func resourceAwsCloudWatchEventRuleRead(d *schema.ResourceData, meta interface{}
 	d.Set("arn", out.Arn)
 	d.Set("description", out.Description)
 	if out.EventPattern != nil {
-		d.Set("event_pattern", normalizeJson(*out.EventPattern))
+		pattern, _ := normalizeJsonString(*out.EventPattern)
+		d.Set("event_pattern", pattern)
 	}
 	d.Set("name", out.Name)
 	d.Set("role_arn", out.RoleArn)
@@ -214,7 +218,8 @@ func buildPutRuleInputStruct(d *schema.ResourceData) *events.PutRuleInput {
 		input.Description = aws.String(v.(string))
 	}
 	if v, ok := d.GetOk("event_pattern"); ok {
-		input.EventPattern = aws.String(normalizeJson(v.(string)))
+		pattern, _ := normalizeJsonString(v.(string))
+		input.EventPattern = aws.String(pattern)
 	}
 	if v, ok := d.GetOk("role_arn"); ok {
 		input.RoleArn = aws.String(v.(string))
@@ -247,3 +252,24 @@ func getStringStateFromBoolean(isEnabled bool) string {
 	}
 	return "DISABLED"
 }
+
+func validateEventPatternValue(length int) schema.SchemaValidateFunc {
+	return func(v interface{}, k string) (ws []string, errors []error) {
+		json, err := normalizeJsonString(v)
+		if err != nil {
+			errors = append(errors, fmt.Errorf("%q contains an invalid JSON: %s", k, err))
+
+			// Invalid JSON? Return immediately,
+			// there is no need to collect other
+			// errors.
+			return
+		}
+
+		// Check whether the normalized JSON is within the given length.
+		if len(json) > length {
+			errors = append(errors, fmt.Errorf(
+				"%q cannot be longer than %d characters: %q", k, length, json))
+		}
+		return
+	}
+}
diff --git a/builtin/providers/aws/resource_aws_cloudwatch_event_rule_test.go b/builtin/providers/aws/resource_aws_cloudwatch_event_rule_test.go
index 5bedff782..e69489777 100644
--- a/builtin/providers/aws/resource_aws_cloudwatch_event_rule_test.go
+++ b/builtin/providers/aws/resource_aws_cloudwatch_event_rule_test.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/aws/aws-sdk-go/aws"
 	events "github.com/aws/aws-sdk-go/service/cloudwatchevents"
+	"github.com/hashicorp/terraform/helper/acctest"
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/terraform"
 )
@@ -165,6 +166,64 @@ func testAccCheckAWSCloudWatchEventRuleDestroy(s *terraform.State) error {
 	return nil
 }
 
+func TestResourceAWSCloudWatchEventRule_validateEventPatternValue(t *testing.T) {
+	type testCases struct {
+		Length   int
+		Value    string
+		ErrCount int
+	}
+
+	invalidCases := []testCases{
+		{
+			Length:   8,
+			Value:    acctest.RandString(16),
+			ErrCount: 1,
+		},
+		{
+			Length:   123,
+			Value:    `{"abc":}`,
+			ErrCount: 1,
+		},
+		{
+			Length:   1,
+			Value:    `{"abc":["1","2"]}`,
+			ErrCount: 1,
+		},
+	}
+
+	for _, tc := range invalidCases {
+		_, errors := validateEventPatternValue(tc.Length)(tc.Value, "event_pattern")
+		if len(errors) != tc.ErrCount {
+			t.Fatalf("Expected %q to trigger a validation error.", tc.Value)
+		}
+	}
+
+	validCases := []testCases{
+		{
+			Length:   0,
+			Value:    ``,
+			ErrCount: 0,
+		},
+		{
+			Length:   2,
+			Value:    `{}`,
+			ErrCount: 0,
+		},
+		{
+			Length:   18,
+			Value:    `{"abc":["1","2"]}`,
+			ErrCount: 0,
+		},
+	}
+
+	for _, tc := range validCases {
+		_, errors := validateEventPatternValue(tc.Length)(tc.Value, "event_pattern")
+		if len(errors) != tc.ErrCount {
+			t.Fatalf("Expected %q not to trigger a validation error.", tc.Value)
+		}
+	}
+}
+
 var testAccAWSCloudWatchEventRuleConfig = `
 resource "aws_cloudwatch_event_rule" "foo" {
     name = "tf-acc-cw-event-rule"