This work reports on the existing situation of ninety-two hospital libraries, located at Mexico's Social Security Institute (IMSS). A descriptive, systems approach was used to explore the physical structure and space of the libraries, staff, furniture, equipment, collections, services, organization and management, and users. Structured interviews were applied to each hospital library, and a questionnaire was used as a tool to collect data. A "control" system, designed to measure the status of each library, was applied through the assignment of values to several indicators, derived from IMSS policy manuals. This procedure helped to identify which library was "more" or "less" adequate to IMSS standards. Within the rank of 10 to 1 (10 = optimum; 1 = minimum), the mean rank of IMSS hospital libraries was 6. The major deficiencies found were those related to furniture (ranked 4) and services (ranked 5) and the lack of library professionals found in 92% of the libraries.