diff --git a/AFNetworking/AFHTTPClient.m b/AFNetworking/AFHTTPClient.m
index 0326f56..3617c02 100755
--- a/AFNetworking/AFHTTPClient.m
+++ b/AFNetworking/AFHTTPClient.m
@@ -237,6 +237,10 @@ static NSString * AFPropertyListStringFromParameters(NSDictionary *parameters) {
     if (!self) {
         return nil;
     }
+	
+	if (!url) {
+		[NSException raise:@"-[AFHTTPClient initWithBaseURL:] nil URL" format:@"`url` must not be nil"];
+	}
     
     // Ensure terminal slash for baseURL path, so that NSURL +URLWithString:relativeToURL: works as expected
     if ([[url path] length] > 0 && ![[url absoluteString] hasSuffix:@"/"]) {