The frequency of smoking in diabetic patients is not appreciably different from that in the general population. As in non-diabetic subjects, smoking is a major cardiovascular risk factor in diabetic patients. For young diabetic patients, smoking has been identified as a risk for macroproteinuric nephropathy. In respect of retinopathy, study results are more controversial. Recent studies also suggest smoking as a risk indicator for extra-articular connective tissue changes and neuropathy. Patients who already present with vascular complications, pregnant women, and women who use oral contraceptive drugs appear to run a particularly high risk by smoking. Stopping smoking reduces the risk of vascular morbidity and mortality in non-diabetic subjects. Although no comparable studies are available for diabetic populations, it should be assumed that the beneficial effects of stopping smoking are applicable to diabetic patients as well. Programmes to encourage diabetic patients to stop smoking are scarce and have not been successful.