BACKGROUND: Although alcohol has been illegal in Iran for over four decades, its consumption persists. This study aims to determine the prevalence and determinants of alcohol consumption in Tehran, the Middle East's third-largest city, using data from the Tehran Cohort Study (TeCS). METHODS: Our study encompasses data from 8420 individuals recorded between March 2016 and March 2019. We defined alcohol use as the lifetime consumption of alcoholic beverages and/or products. We calculated the age- and sex-weighted prevalence of alcohol use in addition to crude frequencies. We also determined the weighted prevalence of alcohol use in both genders. Multivariable logistic regressions were employed to investigate the adjusted odds ratios for the determinants of alcohol use. RESULTS: The mean age of participants was 53.8 ± 12.7 years. The lifetime prevalence of alcohol use was 9.9% (95% confidence interval [95% CI]: 8.3-11.8%) among the total population, with a prevalence of 3.3% (95% CI: 2.4-4.5%) among females and 16.6% (95% CI: 14.3-19.3%) among males. Alcohol use showed a decreasing trend with age in both sexes (women: 4.4% and men: 1.5% per year) as well as in the total population (1.7%). The geographical distribution of alcohol use in Tehran indicated a significantly higher concentration (95% CI: 6.5-13%) in the southern regions compared to other areas. Younger age, higher education levels, smoking, opium use, hyperlipidemia, physical activity, and being overweight determined a higher prevalence of alcohol use. CONCLUSIONS: The prevalence of alcohol use in Tehran is significant and exceeds previous estimates. Policymakers must address the rising incidence of alcohol use, particularly among the younger population.