Diabetes mellitus is a multifaceted disease which intervenes in the personal lives of those afflicted in many different ways. In this study prescription drug use among diabetics was analyzed in order to shed light on the characteristics of diabetic morbidity. Prescription drug use among diabetics and non-diabetics in a total population of 21,000 inhabitants in a defined geographic area were studied. The diabetic population was categorized according to the type of treatment received: insulin treatment, oral anti-diabetic treatment or dietary treatment or dietary treatment only. The pattern of prescription drug use differed between diabetics and non-diabetics and important differences were observed also between diabetics according to type of treatment. Drug use among those treated with insulin and those treated orally was substantially higher than among non-diabetics while the difference between diabetics on dietary regimen and non-diabetics was much smaller. All three treatment groups had considerably higher consumption of cardiovascular drugs than non-diabetics. Additional findings include more frequent antibiotic use among diabetics treated orally and on diet only than among non-diabetics. The use of these drugs was also common among insulin treated diabetics but did not differ significantly from among non-diabetics. Use of psychotropics was more common among diabetics treated with insulin and orally than among non-diabetics.