In this paper the influence of the end-winding heat transfer on the thermal analysis of induction motors is presented. Experimental tests on two induction motor configurations - Open Drip Proof (ODP) and Total Enclosed Fan Cooled (TEFC) frames – are performed and the heat transfer coefficients are determined and validated in a lumped thermal analysis network. The cooling effect of the wafters present in the induction motor cage end-rings is also discussed.