Currently, the life expectancy of people living with the human immunodeficiency virus (HIV) and the general population are similar. Hypertension is a major public health issue in Africa and is largely underdiagnosed. Most HIV-infected individuals, especially those on Anti-Retroviral Therapy (ART) have hypertension. Our project aims to determine the prevalence of hypertension and associated factors amongst HIV-infected adults treated by ART in Burundi. A cross-sectional study was conducted among HIV-infected subjects over the age of 20, managed in five healthcare centers for people living with HIV (PLWH). The World Health Organization STEPWISE survey and anthropometric measurements were employed. Blood pressure was measured according to the ESC 2018 recommendations. 1 250 HIV-infected patients aged between 35.4 and 50.2 years were included (18.4% men). The prevalence of hypertension was 17.4% (95% CI 13.2–22.1). Approximately 47.25% of HIV patients with hypertension were previously undiagnosed. Other factors were associated with HTN, such as being overweight (OR 2.88; 95% CI 1.46–5.62), obesity (OR 2.65; 95% CI 1.27–5.55), longer duration of HIV infection: ≥ 10 years (OR 1.04; 95% CI 1.14–3.20), diabetes (OR 2.1; 95% CI 1.37–3.32) and age (OR 1.13; 95% CI 1.09–1.14). Despite their young age, almost 20% of HIV-ART treated patients had hypertension, 50% of these were undiagnosed. Blood pressure monitoring is crucial in these patients, especially those identified as high-risk, with prompt life and disability-saving interventions.