OBJECTIVE - This study characterizes the pharmaceutical treatment of type 2 diabetes from 1989-1990 to 1996-1997 in an elderly cohort. RESEARCH DESIGN AND METHODS - A total of 5,888 adults aged ≥65 years were recruited and attended a baseline clinic visit in 1989-1990 (n = 5,201, original cohort) or 1992-1993 (n = 687, African-American [new] cohort) as participants of the Cardiovascular Health Study. Fasting serum glucose (FSG) was measured at baseline. Medication use was ascertained by drug inventory at all annual clinic visits. Diabetes was defined at baseline as insulin or oral hypoglycemic agent (OHA) use or as having an FSG ≥7.0 mmol/l (126 mg/dl), the current consensus definition of diabetes. RESULTS - A total of 387 (7%) original (FSG = 9.8 mmol/l [177 mg/dl]) and 115 (17%) new (FSG = 10.6 mmol/l [191 mg/dl]) cohort members had pharmacologically treated diabetes at baseline. Among those in the original and in the new cohorts who survived follow-up, respectively, OHA use decreased from 80 to 48% (P < 0.001) and from 67 to 50% (P < 0.003) and insulin use increased from 20 to 33% (P = 0.001) and from 33 to 37% (P = 0.603). There were 396 (8%) original (FSG = 8.8 mmol/l [159 mg/dl]) and 45 (7%) new (FSG = 10.0 mmol/l [181 mg/dl]) cohort members with diabetes untreated at baseline. Among them, respectively, OHA use reached 38 and 30% and insulin use reached 6 and 16% in 1996-1997. CONCLUSIONS - Diabetes was common in this elderly cohort, and >80% of treated patients with diabetes at baseline were not achieving fasting glucose goals of ≤6.7 mmol/l (120 mg/dl). Many untreated at baseline remained untreated after 7 years of follow-up.