A high burden of pain, symptoms and other multidimensional problems persist alongside HIV treatment. WHO policy indicates palliative care as essential throughout the disease course. This study aimed to determine whether palliative care delivered from within an existing HIV outpatient setting improves control of pain and symptoms compared to standard care. A prospective, longitudinal controlled design compared patient outcomes at an outpatient facility that introduced palliative care training to clinicians and stocked essential palliative care drugs, to outcomes of a cohort of patients at a similar HIV care facility with no palliative care, in Tanzania. Inclusion criteria were clinically significant pain or symptoms. Patients were followed from baseline fortnightly until week 10 using validated self-report outcome measures. For the primary pain outcome, the required sample size of 120 patients was recruited. Odds of reporting pain reduced significantly more at intervention site (OR=0.60, 95% CI 0.50-0.72) than at control (OR=0.85, 95% CI 0.80-0.90), p=0.001. For secondary outcomes, longitudinal analysis revealed significant difference in slope between intervention and control, respectively: Medical Outcomes Study-HIV (MOS-HIV) physical score 1.46 vs. 0.54, p=0.002; MOS-HIV mental health 1.13 vs. 0.26, p=0.006; and POS total score 0.84 vs. 0.18, p=0.001. Neither baseline CD4 nor antiretroviral therapy (ART) use was associated with outcome scores. These data are the first to report outcomes evaluating integrated HIV outpatient palliative care in the presence of ART. The data offer substantive evidence to underpin the existing WHO clinical guidance that states an essential role for palliative care alongside HIV treatment, regardless of prognosis.