An experiment is described in which a significant part of the INTERNIST knowledge base for diagnosis in internal medicine is translated into an EXPERT model. INTERNIST employs the largest and broadest knowledge base of all the medical consultation systems that have been developed in recent years. EXPERT is a general system for designing consultation models. The translated model shows reasonable competence in the final diagnostic classification of 431 test cases. There are differences in the internal representation and reasoning relatively uniform manner, this experiment demonstrates the feasibility of transfer of knowledge between large-scale expert systems.