ObjectivesTo determine the prevalence of overweight and obesity among patients with type 2 diabetes who are attending diabetes clinics in northern Tanzania.ResultsIn total 227 type 2 diabetic patients attending diabetes clinics were enrolled. Majority of patients 193 (85.0%) were overweight (44.9%) or obese (40.1%). Of them, 65 (33.7%) were overweight/obese after diagnosis of type 2 diabetes. The prevalence of overweight/obesity was significantly higher in female participants than the males [92.2% vs. 69.2%; OR = 5.10; 95% CI 2.22–11.05]. Regarding the region of residence, Kilimanjaro (100.0%) and Arusha (89.8%) regions had significantly highest prevalence of overweight/obesity compared to Tanga region (69.2%) [χ2 = 32.455, P < 0.001].Electronic supplementary materialThe online version of this article (10.1186/s13104-017-2861-9) contains supplementary material, which is available to authorized users.