diff --git a/Foundation/NSJSONSerialization.swift b/Foundation/NSJSONSerialization.swift
index 8e08b85918..36120e3cbf 100644
--- a/Foundation/NSJSONSerialization.swift
+++ b/Foundation/NSJSONSerialization.swift
@@ -716,22 +716,25 @@ private struct JSONReader {
                 defer { intEndPointer.deallocate(capacity: 1) }
                 let doubleEndPointer = UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>.allocate(capacity: 1)
                 defer { doubleEndPointer.deallocate(capacity: 1) }
-                
                 let intResult = strtol(startPointer, intEndPointer, 10)
                 let intDistance = startPointer.distance(to: intEndPointer[0]!)
                 let doubleResult = strtod(startPointer, doubleEndPointer)
                 let doubleDistance = startPointer.distance(to: doubleEndPointer[0]!)
-                
+
                 guard intDistance > 0 || doubleDistance > 0 else {
                     return nil
                 }
-                
+
                 if intDistance == doubleDistance {
                     return (intResult, intDistance)
                 }
                 guard doubleDistance > 0 else {
                     return nil
                 }
+
+                if doubleResult == doubleResult.rounded() {
+                    return (Int(doubleResult), doubleDistance)
+                }
                 return (doubleResult, doubleDistance)
             }
         }
diff --git a/TestFoundation/TestNSJSONSerialization.swift b/TestFoundation/TestNSJSONSerialization.swift
index 33eadcb209..0e4e09fe9d 100644
--- a/TestFoundation/TestNSJSONSerialization.swift
+++ b/TestFoundation/TestNSJSONSerialization.swift
@@ -468,7 +468,7 @@ extension TestNSJSONSerialization {
                 XCTAssertEqual(result?[1] as? Int,       -1)
                 XCTAssertEqual(result?[2] as? Double,   1.3)
                 XCTAssertEqual(result?[3] as? Double,  -1.3)
-                XCTAssertEqual(result?[4] as? Double,  1000)
+                XCTAssertEqual(result?[4] as? Int,     1000)
                 XCTAssertEqual(result?[5] as? Double, 0.001)
             }
         } catch {
@@ -871,6 +871,7 @@ extension TestNSJSONSerialization {
             ("test_jsonObjectToOutputStreamInsufficientBuffer", test_jsonObjectToOutputStreamInsufficientBuffer),
             ("test_booleanJSONObject", test_booleanJSONObject),
             ("test_serialize_dictionaryWithDecimal", test_serialize_dictionaryWithDecimal),
+            ("test_serializeDecimalNumberJSONObject", test_serializeDecimalNumberJSONObject),
         ]
     }
 
@@ -1214,6 +1215,22 @@ extension TestNSJSONSerialization {
         XCTAssertTrue(JSONSerialization.isValidJSONObject([true]))
     }
 
+    func test_serializeDecimalNumberJSONObject() {
+        let decimalArray = "[12.1,10.0,0.0,0.0001,20,\(Int.max)]"
+        do {
+            let data = decimalArray.data(using: String.Encoding.utf8)
+            let result = try JSONSerialization.jsonObject(with: data!, options: []) as? [Any]
+            XCTAssertEqual(result?[0] as! Double, 12.1)
+            XCTAssertEqual(result?[1] as! Int, 10)
+            XCTAssertEqual(result?[2] as! Int, 0)
+            XCTAssertEqual(result?[3] as! Double, 0.0001)
+            XCTAssertEqual(result?[4] as! Int, 20)
+            XCTAssertEqual(result?[5] as! Int, Int.max)
+        } catch {
+            XCTFail("Failed during serialization")
+        }
+    }
+
     fileprivate func createTestFile(_ path: String,_contents: Data) -> String? {
         let tempDir = NSTemporaryDirectory() + "TestFoundation_Playground_" + NSUUID().uuidString + "/"
         do {