To estimate the current lifetime prevalence of urolithiasis at the national level in Iran and investigate the potential influential demographic factors in different geographical areas. Materials and methods: An epidemiological study was conducted between October 2020 and November 2022 in 31 provinces of Iran at the national level. Data was obtained through telephone interviews with households. Items in the interview included questions about the current and past episodes of urolithiasis, family history of urolithiasis, and demographic and environmental variables of potential interest in urolithiasis. Results: A total of 44186 participants were investigated from 31 provinces of Iran. The overall percentage of those with lifetime prevalence of urolithiasis was 6.6%, including 7.9% for males and 5.3% for females (P<.001). In addition, with regard to the residential location, men were 53% (7.9% vs. 5.2%) more susceptible than women to urinary stones in urban areas and 36% (7.8% vs. 5.7%) more susceptible in rural areas. Out of 31 provinces, the Sistan-baluchistan province had the highest lifetime prevalence (15.6%) and the Golestan province had the lowest (2.1%). The lifetime prevalence of urolithiasis in the rural areas was 6.8% versus 6.5% in the urban areas (P=.29). Regarding age differentiation, the lifetime urolithiasis prevalence has increased up to the age of 70 years. In addition, the most prominent increase in the lifetime prevalence was observed in the age range of 20 to 60 years (from 0.9% to 11.8%). The ethnicity with the highest lifetime prevalence rate of urolithiasis was the Baluch ethnicity (18%). Conclusion: generally, 6.6% of Iranian population suffers from urinary stones during their lifetime. Urolithiasis prevalence has increased 0.06% annually compared to the latest national study that took place 15 years ago. This increasing trend seems to be less prominent than other countries. According to our findings, urinary stones are more prevalent in men than in women and in the third to sixth decade of life regardless of gender. Baluch ethnicity is associated with the highest lifetime prevalence rate of urolithiasis and there is no significant difference between rural and urban areas. However, the ratio of male to female risk of urolithiasis is higher in urban areas compared to rural areas.