Kapetan Mitrousi is a former municipality in the Serres regional unit, Greece. Since the 2011 local government reform it is part of the municipality Serres, of which it is a municipal unit. It is located in the west-central part of the Serres regional unit and has a population of 4,125 inhabitants and a land area of 87.485 km². The seat of the municipality was the town of Provatas. Its other communities are Mitroúsi, Anagénnisis (523), Áno Kamíla (546), Vamvakiá (395) and Monokklisia (233).