Background: Adiponectin is a protein produced by the adipose tissue, exhibits potential antiatherogenic properties and is involved in the pathogenesis of insulin resistance. Adiponectin levels are decreased in patients with cardiovascular diseases and type 2 diabetes (DM). Aim: To assess the changes in adiponectin levels following acute myocardial infarction (MI) and to evaluate the correlation between adiponectin and C-reactive protein (CRP) in patients with DM. Methods: Coronary angiography was performed in 56 patients with acute MI - 33 patients with DM (23 men, 10 women, mean age 64.0 +/- 11.7 years) and 23 non-diabetic subjects (17 men, 6 women, mean age 58.6 +/- 9.9 years). All the patients underwent a medical examination and their body mass indexes and waist-to-hip ratios were calculated. Venous blood samples were collected 24 hours, 5 days and 3 weeks following admission. Results: Plasma adiponectin levels in non-diabetic patients were significantly higher during the postinfarction recovery period than in the acute phase of MI (7.9 +/- 3.5 mu g/mL vs 7.0 +/- 2.7 mu g/mL). Plasma adiponectin levels in diabetic patients were significantly lower on Day 21 compared to Day 5 (6.0 +/- 2.5 mu g/mL vs 6.7 +/- 3.1 mu g/mL). The changes in plasma adiponectin levels (the difference in plasma adiponectin levels between Days 5 and 21) negatively correlated with CRP levels (r = -0.41, p = 0.001). Adiponectin levels were significantly associated with waist circumference (T2DM: r = -0.34, p = 0.04; control group: r = -0.48, p = 0.001). Conclusions: Plasma adiponectin levels in diabetic patients with acute MI were significantly lower during the postinfarction recovery period. These findings suggest a higher and longer adiponectin utilisation in the regeneration process. A strong inflammatory activity in the atheromatous plaque may decrease plasma adiponectin levels.