I am having the toughest time encoding a URL that contains a query string. What I want to do is open a webbrowser control to a URL. I've done this several times before with no problems. Only difference this time - the URL has a query string on the end. http://my.host.com/path?address=123 Main Street Now, of course, "123 Main Street" needs to be encoded first. This is where I am having the trouble. The following example code illustrates my problem: Code: NSString *myUrl = [@"123 main St" stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]; NSLog(myUrl); I would expect the output to be "123%20main%20St". But instead, the output is garbage. Can anyone tell me why this is? Is this a bug?