Transformations from the Enterprise Distributed Object Computing (EDOC) to Enterprise JavaBeans (EJB) are examined herein from the point of view of an efficiency characteristic of result models. Transformations are composed of mapping operations. Mapping operations map an element or a group of elements of the EDOC model into an element or a group of elements of the EJB model. A standard proposal of mapping operations is defined by the Object Management Group (OMG). Alternative mapping operations, which generate EJB models of a better efficiency characteristic under certain circumstances, are proposed. Rules for composing mapping operations into EDOC – EJB transformations are suggested and illustrated by examples of EDOC – EJB transformations.