Mexican pharmacies play an important adjunct health care role in sexually transmitted disease prevention and treatment. In light of the rapid spread of the AIDS pandemic, research was initiated in 1989 to investigate the feasibility of pharmacies assisting in AIDS and STD prevention and control through community education and condom promotion. This study was implemented in three stages: a needs assessment, development of a training course and complementary materials, and an evaluation of the course and materials. The instruments used in the needs assessment were a KAP questionnaire and 'mystery shopper' visits to pharmacies. The evaluation design utilized pre- and post-tests, condom sales tracking and 'mystery shopper' visits. The needs assessment found that pharmacy employees have some basic knowledge about AIDS and STDs, but lack important information and do not communicate effectively with clients in spite of client interest in these topics. Pharmacy workers expressed great in learning more about AIDS and STDs. The evaluation of the intensive 8-hour course and supporting materials showed that, when given together, the course and materials increased short term knowledge about AIDS and condom use. However, the interventions were less successful in achieving longer term information retention, transfer of knowledge to clients or in influencing condom sales. Adjustments in the training course content and in participant recruitment strategies are recommended.