Fears about the transmission of the human immunodeficiency virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) have emerged in health-care professionals who come into frequent contact with blood and bodily fluids. The present case describes an orthopedic surgeon with a one-year history of severe obsessive compulsive disorder involving a fear of AIDS. Despite a behavioral program of exposure and response prevention, no appreciable treatment gains were made. Several factors are examined that may have contributed to his treatment failure. In particular, adherence to the Centers for Disease Control guidelines regarding the prevention of HIV transmission may have compromised the implementation of an efficacious behavioral program. Also, the patient's overvalued ideation about his personal risk for HIV infection and potential for infecting others no doubt presented an obstacle to treatment. Although excessive, his concerns were nonetheless valid given his medical training and in many respects parallel fears expressed by other health-care professionals. Implications for treatment are discussed.