The theory for the plastic flow of thick‐walled tubes is discussed for a material having an arbitrary true stress‐strain curve, loaded by any combination of internal pressure, external pressure, and end load, where the strains may become large necessitating the use of finite true strain definitions. Comparisons are made of the finite strain theory, the infinitesimal strain theory, and experimental results for the special case of a closed end thick‐walled tube of aluminum. The comparison shows that the infinitesimal strain theory is considerably in error even at moderate strain values. The finite strain theory appears to be satisfactory even for strains somewhat beyond the value for the local bulging of thick‐walled tubes.