Reports of preventable illness due to medication errors are widespread in Canada. However, quantifying the magnitude of the problem has been hampered by a lack of measurement tools. Canadian-specific indicators, or performance measures, of safe medication use do not exist. The objective of this study was to develop a set of Canadian consensus-based indicators for the safe use of medication for both in-patient and outpatient settings. A panel of 20 national experts was established from a convenience sample of experts representing medicine, nursing, pharmacy, research and decision-makers in hospitals and community settings across Canada. After creating a list of potential indicators from the literature, the final consensus set was chosen by the panel using a Delphi survey process via e-mail. After three rounds, consensus was obtained on 20 medication-use safety indicators: seven indicators were related to systems of care, five to prescribing/ordering, three to monitoring/assessment, three to medication administration, one to preparation and dispensing and one to purchasing/inventory management. Seventeen of the indicators measure a process of care (in contrast to health outcome); at least 10 have applications outside the in-patient setting. The resulting 20 medication-use safety indicators are diverse in scope and should be applicable in a variety of practice settings. These indicators may provide clinicians and decision-makers with valuable tools to assess the safety of medication-use systems.