BACKGROUND: Previous research has documented low levels of persistence with prescribed hypertension treatment in Canada. With growing recognition of the value of appropriate drug therapy, rates of persistence may be improving over time. The purpose of this study was to examine persistence with prescribed hypertension treatment among newly treated community-dwelling seniors in British Columbia. METHODS: BC PharmaCare data was used to determine the cohort of seniors who were newly-treated hypertensives over the period 1993 to 2000. Medical and hospital claims from the BCLHD were searched for diagnoses indicating the presence of essential hypertension and potentially confounding conditions. Rates of persistence with drug therapy were analysed, accounting for patient, age, sex, clinical complexity, the existence of potentially confounding conditions, and type of drug first prescribed. RESULTS: For the period 1993 to 2000, 82,824 seniors were identified as new users of hypertension drugs with diagnosed essential hypertension. Fifty-one percent of these newly-treated hypertensives filled a contiguous series of hypertension prescriptions for at least one full year. There was a slight improvement in the rate of persistence over time (p<0.001). Evidence of specific co-morbidities that potentially complicate essential hypertension increased the likelihood of persistence among first-time users (p<0.001), whereas greater overall clinical complexity decreased the likelihood of persistence (p<0.001). Persistence was highest amongst patients initiated on newer anti-hypertensive drug therapies. CONCLUSIONS: Despite modest improvement, persistence with hypertension treatment among the elderly is very low. Further research into the reasons for non-persistence would be advanced through primary data collection, including survey-based research. New policies and practices are needed to encourage persistence with evidence-based therapies.