BACKGROUND: Although bisphosphonate is effective for the prevention and treatment of osteoporosis, poor medication compliance is a key-limiting factor. We determined whether alarm clock could improve compliance with weekly bisphosphonate in patients with osteoporosis, by comparing with age- and gender-matched control group. METHODS: Fifty patients with osteoporosis were recruited and participated in alarm clock group. Patients were asked to take orally weekly risedronate for 1 year, and received alarm clock to inform the time of taking oral bisphosphonate weekly. Using the propensity score matching with age and gender, 50 patients were identified from patients with osteoporosis medication. We compared the compliance with bisphosphonate using medication possession ratio (MPR) between two groups. RESULTS: Although there was no significant difference of baseline characteristics between both groups, the mean MPR (0.80±0.33) of alarm clock group was higher than that (0.56±0.34) of control group (P<0.001). CONCLUSIONS: Alarming could improve the compliance with weekly oral bisphosphonate in patients with osteoporosis.