The relationship between left ventricular mass index (LVMI) and insulin sensitivity, postprandial glycaemia, fasting serum triglyceride and adiponectin was investigated in 70 patients with type 2 diabetes. Serum fasting insulin, C-peptide, high-sensitivity C-reactive protein (hs-CRP), glycated haemoglobin (HbA1c), postprandial glycaemia, lipids and fasting serum adiponectin levels were measured. Ventricular hypertrophy was assessed at rest by electrocardiography and echocardiography. Insulin sensitivity was assessed using the homeostasis model assessment index (HOMA-IR). LVMI was assessed using the Devereux formula. Study patients had lower than normal HOMA-IR, and higher than normal serum fasting insulin levels and LVMI, and tended to have reduced insulin sensitivity. Pearson's correlation coefficient showed a statistically significant correlation between fasting serum adiponectin and LVMI, fasting serum insulin, HOMA-IR, HbA1c, serum postprandial glucose and hs-CRP. There were no statistically significant correlations between LVMI and serum hs-CRP or HOMA-IR. The results indicate the importance of fasting serum adiponectin in the development of cardiovascular complications, such as increased LVMI.