We studied the effects of long-term (12 months) dronabinol in 94 late-stage acquired immunodeficiency syndrome (AIDS) patients (mean CD4 count of 45/mm³) who previously participated in a 6-week study (placebo versus dronabinol). All patients received dronabinol orally—2.5 mg twice daily (90%) or 2.5 mg once daily (10%). Appetite was measured using a visual analogue scale for hunger (VASH). Dronabinol was associated with consistent improvement in mean appetite. Patients previously treated with dronabinol continued to show improvement in VASH (percent change from baseline of 6-week trial: 48.6–76.1% at each month), whereas those previously treated with placebo exhibited substantial improvement in mean appetite, particularly during the initial 4 months of treatment (48.5–69.9%). Thereafter, dronabinol was associated with a VASH change at least twice baseline. Patients tended toward stable body weight for at least 7 months. Adverse events were primarily related to known central nervous system effects of dronabinol. These data support long-term, safe use of dronabinol for anorexia associated with weight loss in patients with AIDS.