An increase in the diabetes prevalence is reported worldwide. We aimed to determine the diabetes prevalence and its risk factors among adults in a rural area of the Democratic Republic of Congo. A cross-sectional study was conducted in 1531 inhabitants, selected by five stages, in the Health Zone of Gombe-Matadi. Diabetes was defined according to the American Diabetes Association and the International Diabetes Federation. Fasting glycemia and/or an oral glucose tolerance test were collected. We measured body mass index, waist circumference and blood pressure. Mann Whitney's and chi-square tests compared respondents with non-respondents. Multivariable logistic regression measured associations between diabetes and its risk factors. Crude and standardized prevalence of diabetes were 6.7% and 5.3%, respectively. Undiagnosed diabetes accounted for 58.8%. The oral glucose tolerance test alone diagnosed 2.6% of cases. Diabetes was more frequent in males, unemployed, obese and hypertensive (p < 0.05). Risk factors for diabetes were being male, aged ≥ 40 years, general and abdominal obesity associated with elderly, family history of diabetes, and hypertension. Diabetes in rural areas of the Democratic Republic of Congo appears to be underdiagnosed. The oral glucose tolerance test provides an opportunity to screen individuals for diabetes in this setting.