A study has been made of heat transfer in three types of internally cooled electrolytic cells employing a common nonaqueous electrolyte. The heat transfer surfaces were in part cathodic and evolved hydrogen gas. The gas evolution was utilized to promote rapid circulation of electrolyte. By varying the relative areas that were gas evolving and nongas evolving, the heat transfer coefficients through the bath side liquid film in contact with these surfaces could be estimated. The film coefficient is greatly enhanced by electrolytic gas evolution and is of the order of 2.5 to 3. Film coefficients appear to follow an exponential law, . Useful application of the effect for purposes of cell design is pointed out.