An experimental study of a "poor boy" downhole gas separator is presented. The poor boy design is simple, robust and unobtrusive, making mandatory its evaluation for further comparison with more elaborated designs. Laboratory results indicate the existence of two separation efficiency regions: a) high, nearly constant, efficiency zone for low liquid flow rates and b) efficiency is an almost linear function of the liquid flow rate, modified by both gas mass flow rate and gas density. A simple formula for separation efficiency calculation is provided to be used for the production of low viscosity oils.