Despite the availability of large funds and considerable efforts to improve access to antiretroviral therapy (ART), coverage of treatment with ART remains low in Democratic Republic of the Congo (DRC). We identified the bottlenecks for adults' access to ART in a semi-rural health zone in DRC, compared ART coverage in the urban and rural area and described the outcomes and yield of different HIV testing settings. An operational model was used to examine bottlenecks in the flow of patients. The study period covered the start of the HIV care programme in April 2006, until December 2008. An estimated 505 People Living With HIV/AIDS (PLWHA), of whom 201 were in need of ART, lived in the health zone. The proportion of PLWHA in need of ART who were actually receiving ART was estimated at 53%. About 6451 adults were tested for HIV, 266 of them were HIV-positive and 163 accessed the HIV care programme. About 106 of the 126–159 eligible patients initiated ART. The main bottleneck was situated at HIV detection. Access to the HIV care programme for the patients testing HIV-positive was identified as the second biggest bottleneck. About 41% of the PLWHA identified in urban areas accessed the HIV care programme, versus 11% of the rural PLWHA, showing a serious inequity. The tuberculosis (TB) programme detected 75% of the total estimated 92 co-infected patients of the health zone. Only 13% of women testing positive in the Prevention of Mother-To-Child Transmission programme accessed the HIV care programme, showing that this bottleneck is greatly accentuated in this specific group. By testing all pregnant women and all TB patients in the health zone, 28% of all PLWHA could potentially be detected in a period of 33 months, showing its great potential in settings with a relatively low HIV prevalence