The aim of this study was to assess parameters of renal function and other determinants of plasma homocysteine in type 2 diabetic patients without coronary heart disease (CHD). Fasting plasma homocysteine, serum cystatin C and serum creatinine were determined in 183 (75 men, 108 women) Type 2 diabetic patients without clinical evidence of CHD. Creatinine clearance was calculated and parameters such as blood pressure, body mass index (BMI), and glycated haemoglobin (HbA(1c)) were assessed. The urine albumin:creatinine ratio was used to classify patients as normo-, micro- or macroalbuminuric. One hundred and ten patients were normoalbuminuric, 67 patients were microalbuminuric and six patients were macroalbuminuric. There was no statistically significant difference in plasma homocysteine concentration between patients with normoalbuminuria and microalbuminuria. There was a trend towards increasing plasma homocysteine with decreasing glomerular filtration rate (GFR) (r=-0.46; P<0.0001). There was statistically significant correlation between plasma homocysteine and age (r=0.37), serum cystatin C (r=0.47), and serum creatinine (r=0.56). Plasma homocysteine concentration was significantly higher in patients with BMI<30 kg/m(2) and showed significant inverse correlation with weight (r=-0.16; P=0.03) and body mass index (r=-0.24; P=0.001). Homocysteine and serum creatinine were significantly higher in males than females and higher in smokers than non smokers but was not associated with glycemic control and duration of diabetes. In conclusion, elevated homocysteine concentration in patients with type 2 DM without CHD is related to age, gender, smoking, BMI and GFR. Follow up studies will provide further information on the association between hyperhomocysteinemia and the development of cardiovascular disease.