Diabetic patients have higher cardiovascular risk than non-diabetic subjects, and fibrinogen has been reported to be one of the independent predictors for diabetic vascular complications. We examined 101 subjects (24 men, 77 women) who were newly diagnosed with type 2 diabetes. Thirty non-diabetic subjects were recruited as controls. The mean (standard deviation, SD) baseline fibrinogen concentrations in men and women were 3.87 (1.17) and 3.42 (1.00) g/L, respectively (not significantly different). Of these 101 subjects, 70 were treated with diet alone and 31 were treated with oral agents. After a mean (SD) follow-up period of 2.38 (0.63) years, there was an 18.5% increase in the fibrinogen concentration from 3.53 (1.06) g/L at baseline to 3.97 (1.07) g/L at follow-up (P < 0.001). The normal subjects had a mean (SD) follow-up period of 1.17 (0.38) years, and showed no significant change in their fibrinogen concentrations from 3.49 (0.90) g/L at baseline to 3.15 (0.61) g/L at follow-up. In the 101 diabetic subjects, only changes in plasma triglyceride correlated with the changes in fibrinogen concentration. Using multivariate analysis with age, sex, duration of diabetes, baseline and changes in body mass index, blood pressure, glycaemic and lipid parameters as independent variables (R2 = 0.106, F= 6.840, P = 0.011), triglyceride (beta = 0.282, P = 0.011) was identified as the only independent variable that predicted the changes in the fibrinogen concentrations. Improved glycaemic control was not accompanied by a reduction in plasma fibrinogen concentration.