1. A new type research ward has been constructed at Rockland State Hospital.2. The reasons why we felt it necessary to alter the existing ward are outlined, and the old and new plans shown.3. Unique features of this new ward are described.4. The above features are of significance to our researches at Rockland State Hospital, but the authors feel that the problems posed and the architectural solutions arrived at may be of value to other investigators since it permits:a) recording of patient's behavior without interaction with the observer;b) absence of knowledge of the patient as to when he is and when he is not being observed;c) observation for extended periods of time;d) patient selection of any of four different "environments" without loss of continuous observations by the observer;e) the recording of reactions in each of these environments;f) permanent recording (tape, silent film or sound film) of selected segments of behavior for later analysis;g) maximum utilization of available personnel which facilitates the accurate and complete collection of urine, feces and other specimens upon which physiological and biochemical studies depend.