Background/aim: We calculated the homeostatic model assessment (HOMA) for estimating insulin sensitivity and beta-cell function in normal, healthy nondiabetics with infections (malaria, influenza, HIV, Helicobacter pylori, Chlamydia pneumoniae, and hepatitis C virus), type 2 diabetic black patients, and healthy controls from Kinshasa, DR Congo. Materials and methods: A case-control study was carried out between 2006 and 2007 for black Central African participants managed for HOMA.Results: In total, 219 patients and 110 healthy controls were matched for sex and age. The hyperbolic product for 85 infected patients occupied an intermediate position between the hyperbolic product for 110 controls and that of 134 type 2 diabetics. Inflammation/oxidative stress was present in all infected patients, as well as in the type 2 diabetics. Of the patients, 39.3% and 49.8% had insulin resistance and metabolic syndrome, respectively. Insulin resistance was more prevalent in nondiabetics with inflammation/oxidative stress (47.1%; P = 0.041) than in type 2 diabetics (34.3%). Type 2 diabetics had higher insulin sensitivity and lower beta-cell function but a similar HOMA-IR score. Conclusion: We recommend the assessment of insulin resistance in Central African patients with severe infections and type 2 diabetes.