Objective: To identify and characterize patterns of use of complementary and alternative (CAM) therapies by human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) patients participating in clinical trials in a research setting. Design: A descriptive survey using a nonrandom sample of 100 patients was conducted over 17 months, using a 99-item interview schedule adapted from a previous study. Setting: National Institutes of Health (NIH) Warren G. Magnuson Clinical Center. Subjects: Patients diagnosed with HIV/AIDS, participating in clinical research protocols at the National Institute of Allergy and Infectious Diseases and the National Cancer institute (NCI) at the NIH. Results: Ninety-one percent (91%) had used at least one CAM therapy, as defined by a 1993 study by Eisenberg et al., sometime in their lives. Postdiagnosis, 84% used at least one CAM therapy with an average of just fewer than 5. The increase in frequency of use from 64% prediagnosis was significant (p2 = 0.019). Therapies that became significantly more popular postdiagnosis were, imagery (p2 = 0.00012), high-dose vitamins, (p2 = 0.000019), weight gain (p2 = 0.000244), massage (p2 = 0.00091), relaxation (p2 = 0.0033), herbals (p2 = 0.013), spiritual (p2 = 0.024), and acupuncture (p2 = 0.035). They were primarily used for HIV/AIDS-related problems: dermatological, nausea, depression, insomnia, and weakness. There was a high level of agreement that benefits of CAM use were: feeling better, 51 (98.1%), increased coping, 52 (100%), feeling in control, 44 (88.5%), and enhanced treatment outcome, 49 (94.2%) with 32 (61%) stating CAM was as, or more effective than conventional treatment. Fifty-three percent (53%) were specifically asked by physicians whether they were using adjunct therapies. Conclusions: Subjects used a variety of CAM therapies to cope with their diseases and rigors of treatment and clinical trials. Further research is needed to identify CAM therapies that may be used as adjunct treatments during clinical trials.