The author presents a conceptual model for evaluating ego functions in terms of the processes which occur in response to internal and external changes. The emphasis is on how effective such a process is in coping with the stress situation. The ego responses are categorized as to whether they are coping mechanisms, defense mechanisms, or failures. The heuristic and therapeutic value presented is largely concerned with the aspect of adaptation and does not deal with the other psychoanalytic frames of study, such as topographical, economic, and genetic. Although the model may offer a structure for studying adaptation, the particular ego functions cited and followed through are sufficiently diverse from the usual psychoanalytic categories to present some terminological confusion.