This analysis provides an in-depth look at the number and types of drugs used by seniors, and compares drug use among seniors living in long-term care (LTC) facilities and those living in the community. METHODS: Data from the National Prescription Drug Utilization Information System (NPDUIS) Database, housed at CIHI, as submitted by eight Provincial drug programs and one Federal drug program in Canada, including drug claims for approximately 70% of Canadian seniors. RESULTS: In 2012, nearly two-thirds (65.9%) of seniors had claims for 5 or more drug classes, and more than one-quarter (27.2%) of seniors had claims for 10 or more drug classes. The proportion of seniors age 85 and older with claims for 10 or more drug classes (39.3%) was double that of seniors age 65 to 74 (20.0%). Six of the 10 drug classes most commonly used by seniors were cardiovascular-related. The most commonly used drug class was statins, which are used by almost half of seniors (46.6%). More than one-third of seniors (38.9%) had claims for a drug on the Beers list—a list of drugs identified as potentially inappropriate to prescribe to seniors. More than half of seniors living in LTC facilities were using 10 or more different drug classes (60.9%), more than double the proportion among seniors living in the community (26.1%). In LTC facilities benzodiazepine use was double the rate, antidepressant use triple the rate and antipsychotic use nine times the rate among seniors living in the community. CONCLUSIONS: Findings suggest a high proportion of seniors, particularly those living in LTC facilities may be at risk for drug interactions and other adverse events due to the number of medications they are taking. This illustrates the importance of medication management strategies for seniors, and the need for communication between health care providers regarding seniors’ drug regimens.