BACKGROUND: The average duration of diabetes and predictive factors of macrovascular complications in Korean diabetic patients remain to be elucidated. This study examines the average duration of diabetes up to the onset of macrovascular complications and clinically important factors of early development of these complications in Korean type 2 diabetic patients. METHODS: Clinical characteristics in type 2 diabetics with (n = 121) and without macrovascular complications (n = 115) were analyzed. In addition, early onset (< or = 5 years, n = 54) and late onset groups (> 5 years, n = 67) were compared, as were the clinical characteristics between male and female patients in the macrovascular complications group. RESULTS: The average duration of diabetes was 8.7 +/- 7.8 years in the macrovascular complications group. Average age, systolic and diastolic blood pressures and smoking history were all higher in the macrovascular complications group than the control group. However, HbA1c levels and prevalence of microvascular complications were higher in the controls. Average age was lower in the early onset group and many more patients of that group had a smoking history. In the analysis based on sex, marcrovascular complications developed earlier in male patients. In addition, the prevalence of family history of diabetes was higher in males and 77.8% of male patients had a smoking history (female: 3.4%). CONCLUSION: Our study confirms that older age, high blood pressure and smoking history are major risk factors for the development of macrovascular complications. Moreover, a smoking history in males can be both risk and predictive factors for earlier development of macrovascular complications in Korean type 2 diabetic patients. We also found that several clinical characteristics including age, family history of diabetes, hypertension and smoking history, vary between the sexes, and these findings can provide useful indices for the prevention of macrovascular complications.