BACKGROUND: To identify the association of meteorological factors/ambient air pollutants with medical care utilization for urolithiasis and estimate the effect size/time lags. METHODS: This is a population-based time-series analysis of 300,000 urolithiasis cases from eight large metropolitan areas in Korea. Seventeen meteorological factors and ambient air pollutants were measured daily during 2002-2017 for each metropolis. Data on daily medical utilization owing to urolithiasis were collected. A generalized additive model was used while factoring in the nonlinear relationship between meteorological factors/ambient air pollutants and urolithiasis and a time lag of ≤10 days. A multivariate analysis was performed. Backward elimination with an Akaike information criterion was used for fitting the multivariate model. RESULTS: Urolithiasis was significantly associated with average temperature, diurnal temperature range, sunshine duration, particulate matter (PM) ≤2.5 μm, and carbon monoxide (CO) levels. The incidence of ureteral stones was positively correlated with average temperature, PM ≤2.5 μm level, and CO level (time lags 0-9, 2-4, and 0-9 days, respectively). The incidence of renal stones was positively correlated with PM ≤2.5 μm and CO levels (time lags 2-4 and 0-9 days, respectively). PM≤2.5 μm (0.05 and 0.07% per 10 μg/m^3) and CO (2.05 and 2.25% per 0.1ppm) conferred the highest excess risk on ureteral and renal stones. CONCLUSIONS: Urolithiasis is affected by various meteorological factors and ambient air pollutants, PM PM≤2.5 μm, and CO levels may be novel potential risk factors for this condition.