What happens if you unknowingly use someone else’s trademark? It still can be trademark infringement and you can still have liability for confusing the public. Trademark law is about helping the public make more efficient decisions by not being confused as to the source. If you get a federally registered trademark it covers the entire nation whether or not you’re using it all over the nation. But if you don’t get a federally registered trademark your rights to your trademark are limited to the area in which you are using it. It can be a problem and it can be trademark infringement if you are using somebody else’s trademark even without knowing it. If you receive a cease and desist letter from another trademark holder I recommend you contact a knowledgeable trademark attorney. I’m Wayne Carroll with Inspired Idea Solutions law firm. To find out more give me a call.