To determine the pattern of treatment of diabetes and its complications, data from a specific study performed by the French healthcare system were used. Between the 10th and 15th of May 1993, all the prescriptions for which a reimbursement was asked were registered with the age and sex of the subject for whom the prescription was written. Patients with a prescription of antidiabetic (AD) drugs were classified as diabetic. Among the 125,883 prescriptions at least one antidiabetic drug is present on 3339 (2.7%). The mean number of AD drugs prescribed is 1.3 and varies from 1 to 4. Eighty five per cent of the patients are treated with oral anti diabetic drugs alone (OAD) and 15% with insulin, alone (89%) or in association with OAD (11%). The total number of drugs (antidiabetic drugs included) prescribed for one patient varied from 1 to 18 (mean: 5.7) and is higher in women than in men. Drugs which are indicated in cardiovascular diseases (lipids lowering, blood pressure lowering drugs) are more frequent on "diabetic" prescriptions than on non diabetic ones. Most (66%) of the prescriptions are written on special forms (100% reimbursement). These forms are more often used for insulin treated patients (87%) than for non insulin treated patients (62%). Most (91%) of the prescriptions are written by a general practitioner. Taking into account the antidiabetic drugs specificity and the data base used, these results can be extrapolated to the all french diabetic population.