1. The specific role of physical activity in the treatment of type 2 diabetes is still subject to discussion. A randomized prospective study was performed, investigating both the influence of physical training on metabolic control and the feasibility of physical training in the elderly. 2. A total of 58 patients (mean age: 62 +/- 5 years; range: 55-75 years) with type 2 diabetes were randomized to either a physical training or a control programme. The training programme consisted of three sessions a week, aiming at 60-80% of the maximal oxygen uptake (VO2max). The 12 week supervised period was followed by a 14 week non-supervised one. The control group followed an educational programme. VO2max was assessed during exercise on a cycle ergometer. Glycosylated haemoglobin (HbA1c) was used as a measure for glucose control, and an insulin tolerance test was performed to test insulin sensitivity. Multivariate analysis of variance, with repeated measures design, was used to test differences between groups. 3. Fifty-one patients completed the study. VO2max was higher in the training group than in the control group both after 6 weeks (P < or = 0.01 between groups) and after 26 weeks [training group: 1796 +/- 419 ml/min (prestudy), 1880 +/- 458 ml/min (6 weeks), 1786 +/- 591 ml/min (26 weeks); control group: 1859 +/- 455 ml/min (prestudy), 1742 +/- 467 ml/min (6 weeks), 1629 +/- 504 ml/min (26 weeks)]. Blood glucose control and insulin sensitivity did not change during the study. Levels of total triacylglycerols, very-low-density lipoprotein-triacylglycerols and apolipoprotein B were significantly lower after 6 weeks (P < or = 0.01, P < or = 0.05, P < or = 0.05 between groups respectively), and so was the level of total cholesterol after 12 weeks of training (P < or = 0.05 between groups). 4. Physical training in obese type 2 diabetic patients over 55 years of age does not change glycaemic control or insulin sensitivity in the short-term. Regular physical activity may lower triacylglycerol and cholesterol levels in this group of patients. 5. Finally, physical training in motivated elderly type 2 diabetic patients without major cardiovascular or musculoskeletal disorders is feasible, but only under supervision.