Since 1969, the Pacific Southwest Regional Medical Library Service (PSRMLS) has provided programs and services to promote the development of hospital libraries, both by encouraging the establishment of new libraries and by aiding existing libraries in improving services and resources. This document reports the results of an evaluation project designed to determine the development of hospital libraries in the Pacific Southwest Region over the past 15 years; measure the impact of PSRMLS; determine which hospitals in the region have organized libraries; and gather baseline data on hospital and other health sciences libraries for future comparison. Data gathered from a questionnaire were compared to the results of two previous surveys made in 1969 and 1971. Following an executive summary and introduction, the report is divided into six sections: (1) methodology of data collection and analysis; (2) hospital library development, including paired data comparison, composite data comparison, and existence of core services and resources; (3) the impact on the region of PSRMLS programs and services; (4) the identification of hospital libraries within the region; (5) the future use of baseline data; and (6) summaries of the study results. In addition to tables and charts presented in the text, appendixes contain detailed data breakdowns. (THC)