diff --git a/AFNetworking/AFHTTPClient.m b/AFNetworking/AFHTTPClient.m
index dafca4e..42b2b40 100644
--- a/AFNetworking/AFHTTPClient.m
+++ b/AFNetworking/AFHTTPClient.m
@@ -176,6 +176,8 @@ static NSString * AFPropertyListStringFromParameters(NSDictionary *parameters) {
 #if __IPHONE_OS_VERSION_MIN_REQUIRED
     // User-Agent Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.43
     [self setDefaultHeader:@"User-Agent" value:[NSString stringWithFormat:@"%@/%@ (%@, %@ %@, %@, Scale/%f)", [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleIdentifierKey], [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleVersionKey], @"unknown", [[UIDevice currentDevice] systemName], [[UIDevice currentDevice] systemVersion], [[UIDevice currentDevice] model], ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] ? [[UIScreen mainScreen] scale] : 1.0)]];
+#elif __MAC_OS_X_VERSION_MIN_REQUIRED
+    [self setDefaultHeader:@"User-Agent" value:[NSString stringWithFormat:@"%@/%@ (%@)", [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleIdentifierKey], [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleVersionKey], @"unknown"]];
 #endif
     
     self.operationQueue = [[[NSOperationQueue alloc] init] autorelease];