OBJECTIVES: As an aid to diabetes clinical care and research we sought to develop a valid and reliable instrument: the Diabetes Medication Satisfaction Tool (DMSAT) to measure patient satisfaction with a broad spectrum of diabetes treatment regimens in primary care. This was a cross-sectional survey study to develop and test a self-report questionnaire on satisfaction with diabetes medications. METHODS: Item content was obtained from focus groups of patients attending community health clinics, pre-tested in a sample of 55 patients with Type 2 diabetes, and examined in a sample of 140 patients of a group family practice with a diagnosis of diabetes and prescribed medical therapy. Factor analysis and tests of subscale and total score means across clinical groups were used to examine measurement characteristics. RESULTS: Sixteen items were retained assessing four distinct medication treatment experiences: ease and convenience, lifestyle burdens, well-being, and medical control. Construct validity of the scales and total score were demonstrated by statistically significant (p<0.05) associations with treatment complexity, follow-up visits, self-rated glucose control, health worries, and A1c in the last six months. Internal consistency reliability coefficients for the scales and total score ranged from 0.89 to 0.95. CONCLUSION: The results of this study suggest that the DMSAT has good construct validity and reliability, and is sensitive to levels of clinical and patient reported outcomes that relate to treatment burden and Type II diabetes control. The DMSAT offers a comprehensive assessment of the patient acceptability and satisfaction with the use of diabetes medication therapy in their daily life. Testing across two independent patient samples showed DMSAT scores correspond to clinically relevant outcomes.