diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
index 9bf9c4f8d1d27d2c3d0552799ebc58b55bd483b1..acc20be74383dbfc1486363787f4de6e7fc37913 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
@@ -527,8 +527,8 @@
                     HKQuantity *quantity = sample.quantity;
                     double value = [quantity doubleValueForUnit:unit];
                     
-                    NSString *startDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.startDate];
-                    NSString *endDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.endDate];
+                    int startDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.startDate];
+                    int endDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.endDate];
                     
                     NSString *deviceName = sample.device.name ? sample.device.name : @"";
                     NSString *deviceManufacturer = sample.device.manufacturer ? sample.device.manufacturer : @"";
@@ -552,8 +552,8 @@
                     
                     NSDictionary *elem = @{
                                            @"value" : @(value),
-                                           @"startDate" : startDateString,
-                                           @"endDate" : endDateString,
+                                           @"startDate" : @(startDateTimestamp),
+                                           @"endDate" : @(endDateTimestamp),
                                            @"deviceName" : deviceName,
                                            @"deviceManufacturer" : deviceManufacturer,
                                            @"deviceHardware" : deviceHardwareVer,
@@ -619,13 +619,13 @@
             dispatch_async(dispatch_get_main_queue(), ^{
                 
                 for (HKCorrelation *sample in sampleObjects) {
-                    NSString *startDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.startDate];
-                    NSString *endDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.endDate];
-                    
+                    int startDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.startDate];
+                    int endDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.endDate];
+
                     NSDictionary *elem = @{
                                            @"correlation" : sample,
-                                           @"startDate" : startDateString,
-                                           @"endDate" : endDateString,
+                                           @"startDate" : @(startDateTimestamp),
+                                           @"endDate" : @(endDateTimestamp),
                                            };
                     [data addObject:elem];
                 }
@@ -683,8 +683,8 @@
                 for (HKCategorySample *sample in sampleObjects) {
                     NSInteger val = sample.value;
                     
-                    NSString *startDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.startDate];
-                    NSString *endDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.endDate];
+                    int startDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.startDate];
+                    int endDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.endDate];
                     
                     NSString *valueString = [NSString stringWithFormat:@"%d", val];
                     
@@ -710,8 +710,8 @@
                     
                     NSDictionary *elem = @{
                                            @"value" : valueString,
-                                           @"startDate" : startDateString,
-                                           @"endDate" : endDateString,
+                                           @"startDate" : @(startDateTimestamp),
+                                           @"endDate" : @(endDateTimestamp),
                                            @"deviceName" : deviceName,
                                            @"deviceManufacturer" : deviceManufacturer,
                                            @"deviceHardware" : deviceHardwareVer,
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Utils.h b/RCTAppleHealthKit/RCTAppleHealthKit+Utils.h
index 2543ac0681763758bc05e096e9b7d61242a45908..738129fe1c8b0859e093ef60e042274cd98671f3 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Utils.h
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Utils.h
@@ -12,6 +12,7 @@
 
 + (NSDate *)parseISO8601DateFromString:(NSString *)date;
 + (NSString *)buildISO8601StringFromDate:(NSDate *)date;
++ (int)buildTimestampFromDate:(NSDate *)date;
 + (NSPredicate *)predicateForSamplesToday;
 + (NSPredicate *)predicateForSamplesOnDay:(NSDate *)date;
 + (NSPredicate *)predicateForSamplesBetweenDates:(NSDate *)startDate endDate:(NSDate *)endDate;
diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Utils.m b/RCTAppleHealthKit/RCTAppleHealthKit+Utils.m
index 555e51332e7b398f4b00d7d41a09e6a4d62d244d..9567857689398d82c9f7e147910298b7876d909b 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Utils.m
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Utils.m
@@ -33,6 +33,14 @@
 }
 
 
++ (int)buildTimestampFromDate:(NSDate *)date
+{
+    NSTimeInterval interval = [date timeIntervalSince1970];
+    NSNumber *timeStampObj = [NSNumber numberWithDouble: interval];
+    return [timeStampObj intValue];
+}
+
+
 + (NSPredicate *)predicateForSamplesToday {
     NSDate *now = [NSDate date];
     return [RCTAppleHealthKit predicateForSamplesOnDay:now];