A simple model for thermal analysis of regenerative cooled rocket engines is developed. In this model the multi-dimensional heat conduction in the engine wall is analyzed using the fin effect of cooling channel side walls. A one-dimensional model for the cooling channel flow and heat transfer is used. The coolant properties are evaluated based on the NIST database. The present model is used to perform thermal analysis on two engines: the Space Shuttle Main Engine (a liquid hydrogen cooled engine) and a liquid oxygen cooled engine. Given the simplicity of the present approach its results compare well with other comprehensive models.