The purpose of this study was to assess the concentration of C-reactive protein (CRP) in obese type 2 diabetes mellitus (DM2) patients and its association with macrovascular and microvascular complications. The study group consisted of 80 obese DM2 patients, including 20 macrovascular, 20 microvascular, 20 both macrovascular and microvascular, and 20 with no complications patients. The control group comprised 40 normoglycemic subjects--20 obese and 20 of normal body weight. Highly sensitive CRP and metabolic control parameters were assessed. CRP levels in obese diabetes subgroups and normoglycemic obese were similar and significantly higher than those in nonobese controls. No correlation was found between CRP and diabetes control parameters. There was a strong positive correlation between CRP level and body mass index in all groups. A multivariate analysis showed that DM2 and obesity are independent factors increasing CRP levels. Increased concentration of CRP in obese DM2 patients is related to obesity and diabetes itself. The lack of association between CRP and vascular complications remains unclear.