INTRODUCTION: Uganda was using a threshold of 1000 copies/mL to determine viral non-suppression for antiretroviral therapy monitoring among people living with HIV, prior to this study. It was not clear whether people living with HIV with low-level viraemia (LLV, ≥50 to <1000 copies/mL) would benefit from intensive adherence counselling (IAC). The purpose of this study was to determine the effectiveness of IAC among people living with HIV, receiving antiretroviral therapy, and with LLV in Uganda, to guide key policy decisions in HIV care, including the review of the viral load (VL) testing algorithm. METHODS: This cluster-randomized clinical trial comprised adults from eight HIV clinics who were living with HIV, receiving ART, and had recent VL results indicating LLV (tested from July 2022 to October 2022). Participants in the intervention arm clinics received three once-monthly sessions of IAC, and those in the comparison non-intervention arm clinics received the standard of care. At the end of the study, all participants were re-tested for VL to determine the proportions of those who then had an undetectable VL (<50 copies/mL). We assessed the statistical association between cross-tabulated variables using Fisher's exact test and then modified Poisson regression. RESULTS: A total of 136 participants were enrolled into the study at eight HIV clinics. All 68 participants in the intervention arm completed all IAC sessions. Only one participant in the non-intervention arm was lost to follow-up. The average follow-up time was 3.7 months (standard deviation [SD] 0.2) and 3.5 months (SD 0.1) in the intervention and non-intervention arms, respectively. In total, 59 (43.7%) of 135 people living with HIV achieved an undetectable VL during the study follow-up period. The effect of IAC on attaining an undetectable VL among people with LLV was nearly twice as high in the intervention arm (57.4%) than in the non-intervention arm (29.9%): adjusted risk ratio 1.9 (95% confidence interval 1.0-3.5), p = 0.037. CONCLUSION: IAC doubled the likelihood of an undetectable VL among people living with HIV with LLV. Therefore, IAC has been instituted as an intervention to manage people living with HIV with LLV in Uganda, and this should also be adopted in other Sub-Saharan African countries with similar settings. GOV IDENTIFIER: NCT05514418.