Stockouts of HIV commodities increase the risk of treatment interruption, antiretroviral resistance, treatment failure, morbidity and mortality. The study objective was to assess the magnitude and duration of stockouts of HIV medicines and diagnostic tests in public facilities in Kinshasa, Democratic Republic of the Congo. This was a cross-sectional survey involving visits to facilities and warehouses in April and May 2015. All zonal warehouses, all public facilities with more than 200 patients on antiretroviral treatment (ART) (high-burden facilities) and a purposive sample of facilities with 200 or fewer patients (low-burden facilities) in Kinshasa were selected. We focused on three adult ART formulations, cotrimoxazole tablets, and HIV diagnostic tests. Availability of items was determined by physical check, while stockout duration until the day of the survey visit was verified with stock cards. In case of ART stockouts, we asked the pharmacist in charge what the facility coping strategy was for patients needing those medicines. The study included 28 high-burden facilities and 64 low-burden facilities, together serving around 22000 ART patients. During the study period, a national shortage of the newly introduced first-line regimen Tenofovir-Lamivudine-Efavirenz resulted in stockouts of this regimen in 56% of high-burden and 43% of low-burden facilities, lasting a median of 36 (interquartile range 29-90) and 44 days (interquartile range 24-90) until the day of the survey visit, respectively. Each of the other investigated commodities were found out of stock in at least two low-burden and two high-burden facilities. In 30/41 (73%) of stockout cases, the commodity was absent at the facility but present at the upstream warehouse. In 30/57 (54%) of ART stockout cases, patients did not receive any medicines. In some cases, patients were switched to different ART formulations or regimens. Stockouts of HIV commodities were common in the visited facilities. Introduction of new ART regimens needs additional planning.