To evaluate the characteristics of the drug used for the therapy of chronic diseases, 1588 prescriptions from a sample of 549 continued drug prescription forms were evaluated. Every patient had a mean number of 2.9 drugs, 2.14 diagnoses and 1.41 drugs per diagnosis. The patients over 65 years had a higher number of drugs and diagnoses. A smaller number of diagnoses but a higher number of drugs per diagnoses was found for males. The drug subgroups with higher prescription rates were cardiac drugs (12.3%), diuretics (11.2%) and analgesics (9.9%). The most common diagnoses were hypertension and osteoarthritis, with 17.6% and 13.6% of prescriptions, respectively. A high rate of patients receiving vasodilators (12%) and benzodiazepines (14.7%) was found. The usefulness of the continued prescription forms for the control of chronic treatments is emphasized.