Doesn't that depend on a state by state basis? I know many states are one-party consent.I believe Google Voice has the option to do so. Other than that, I've never looked into it. Only know about GV bc I accidentally hit something it said it was recording the call. It will notify the person you are recording too, btw...in case you wanted to do it all sly like...and they have to know if you ever going to want to use it in the court of law.