OBJECTIVES: This cross-sectional study aims to evaluate the association between calcium and vitamin D supplementation for osteoporosis treatment and the development of kidney stones while investigating the impact of urinary calcium excretion on kidney stone risk among patients receiving this supplementation treatment. DESIGN: The study involved collecting data from 204 Chinese Han patients aged 50-89 with osteoporosis in the southwest region of China. These patients had been on daily doses of 600 mg of calcium carbonate and 0.5 µg alfacalcidol for at least 1 year. The study employed univariate analysis and multivariable logistic regression to identify risk factors for kidney stones, with independent t-tests used to compare differences between groups. SETTING: Data were collected from patients in the southwest region of China, covering the period from July 2019 to December 2023. PARTICIPANTS: The study included 204 patients with osteoporosis, all of whom had been receiving the specified calcium and vitamin D supplements for the duration of the study. RESULTS: The study found that a history of recurrent kidney stones was an independent risk factor for the development of kidney stones. Patients with kidney stones who had a history of recurrent stones exhibited significantly higher levels of 24-hour urinary calcium excretion (1.00±0.62 vs 0.57±0.54, p=0.026) compared with those without such a history. CONCLUSIONS: The results suggest that a history of recurrent kidney stones independently increases the risk of kidney stones in patients undergoing calcium and vitamin D supplementation for osteoporosis, likely due to increased urinary calcium excretion.