A positive temperature coefficient thermister is devised as a thermal probe to determine local heat transfer coefficients in a stirred vessel with a standard Rushton turbine impeller, The effects of aeration and flow patterns on the value of local heat transfer coefficients are discussed. Under most operating conditions, the highest flux is found at the impeller discharge region and the front side of the baffle plates. The mean Nusselt number for Jacket and baffle type heat exchange elements is presented in terms of the modified Reynolds number and the other dimmensionless groups, as the results of the integration of the determind values of local heat transfer coefficients.