Objectives: The objectives of this study were 1) to determine the proportion of people living with HIV/AIDS (PLWHA) at risk of developing malnutrition, 2) to determine the prevalence of malnutrition (BMI < 18.5 kg/m2), and 3) to describe the dietary intake and other nutrition parameters of PLWHA with membership in support groups. Design: Descriptive cross-sectional study. Setting: Six support groups in Gaborone and neighbouring locations. Subjects: Consenting, free living HIV-positive adults 20 to 50 years of age with membership in support groups for PLWHA. Outcome measures: The subjects’ risk of developing malnutrition was established using a modified subjective global assessment (SGA) screening tool. Subjects with an SGA score = 4 were classified as being at high risk of developing malnutrition. Results: From 145 PLWHA screened, 47.5% (n = 69) were found to be at high risk of developing malnutrition (SGA score = 4) and 28.5% (n = 41) were malnourished (BMI < 18.5 kg/m2). In the sample with SGA scores = 4, 52.2% (n = 35) presented with a BMI < 18.5 kg/ m2. These two groups also reported more unintentional weight loss, gastrointestinal symptoms, and other conditions commonly associated with a high risk of developing malnutrition. PLWHA with membership in support groups also had low educational attainment and high unemployment rates. A total of 47% of subjects with an SGA score = 4 needed food assistance. Conclusions: Almost 50% of PLWHA with membership in support groups for PLWHA are at risk of developing malnutrition, while about 30% have a BMI < 18.5kg/m2. Nutrition screening can also help to identify those PLWHA with a BMI > 18.5 kg/m2 who are still at high risk of developing malnutrition. Timely nutrition interventions can therefore be instituted in order to prevent deterioration in nutritional status.