Fatigue is a frequent symptom reported by persons living with HIV disease and one that affects all aspects of quality of life. To improve quality of care of persons with HIV disease, it is important to address all factors that contribute to fatigue. The purpose of this study was to determine the associations of physiological, psychological, and sociological factors with fatigue in an HIV-infected population. With Piper's integrated fatigue model guiding selection, factors examined in this study were hemoglobin, hematocrit, CD4+ cell count, HIV-RNA viral load, total sleep time, sleep quality, daytime sleepiness, HIV-related symptoms, anxiety, depression, and perceived stress. The sample (N = 79) for this descriptive correlational study was recruited from a primary health care association in South Carolina and consisted of 42 (53.2%) HIV-infected women and 37 (46.8%) HIV-infected men between the ages of 24 and 63 years (x = 39.9, s = 7.9). Of the participants, 70 (90%) were African American, 5 (6%) were Caucasian, and 3 (4%) were Hispanic. Using Pearson's r, significant relationships were observed between fatigue and sleep quality, daytime sleepiness, HIV-related symptoms, state anxiety, trait anxiety, depression, and perceived stress. Sleep quality (F5,65 = 12.02, P = 0.0009), state anxiety (F5,65 = 8.28, P = 0.0054), HIV-related symptoms (F5,65 = 4.87, P = 0.0308), and depression (F5,65 = 7.31, P = 0.0087) retained significance in a 3-step, backward stepwise elimination model and accounted for 67% of the variance in fatigue. These findings underscore the need for addressing psychosocial stressors and sleep quality in developing effective care for HIV-infected individuals who experience fatigue.