Two worst possible scenerios -- 1) You have to move twice 2) You have two mortgages. Pick which is the lesser of the two evils, and you have your answer. If you're ok with the possibility that you'd need to find temporary housing while you look for your new home, then sell first. If moving twice can't be an option for you, you'll need to pay two mortgages for some period of time. Hope this helps! Good luck.