We report on field interpretation of HIV self-testing among female sex workers (FSWs) and non-FSWs living in Democratic Republic of the Congo.Two hundred and eight participants [76 (36.5%) FSWs; 132 (63.5%) non-FSWs] were enrolled in Kisangani and Bunia to evaluate their ability to read and interpret the results of a prototype HIV self-test (Exacto Test HIV, Biosynex, Strasbourg, France), according to WHO recommendations. Thirteen standardized tests (6 positive, 5 negative, 2 invalid) were proposed after successive random selection.Two thousand seven hundred and four standardized tests (1248 positive, 1040 negative, 416 invalid) were interpreted; 2435 (90.1%) were correctly interpreted, whereas 269 (9.9%) were misinterpreted. In FSWs and non-FSWs, the test results were similarly correctly interpreted in 87.4% (864/988) and 91.6% (1571/1716), respectively. In multivariate logistic regression analysis, only the variable "educational level" remained strongly associated with the interpretation of positive, negative, and invalid HIV self-test results, but not the variables "commercial sex work" and "language chosen for instructions for use." Incorrect interpretation was significantly higher in participants with insufficient educational level than in those with sufficient education level for positive (13.1% vs 2.6%; adjusted OR: 4.5), negative (22.3% vs 2.6%; adjusted OR: 5.3), and invalid test results (23.8% v 6.4%; adjusted OR: 3.6).Incorrect interpretation of HIV self-test was as common in FSWs and non-FSWs. The lower was the educational level, the greater was the difficulty to interpret results correctly. These observations point that insufficient education level, rather than commercial sex work by itself, constitutes a key factor of incorrect interpretation of HIV self-test.