This study aimed to determine the trends in outpatient cataract surgery and its determinants in the Islamic Republic of Iran between 2006 and 2010. In this cross-sectional study, 106 cataract surgery centres were selected in all provinces by multistage randomized cluster sampling. The number of centres in each province was determined from the number of cataract operations and the number of patient charts examined in each centre was proportionate to the number of cataract operations in that centre. The prevalence of outpatient surgery increased from 46.0% (95% CI, 35.3–56.8) in 2006 to 51.4% (95% CI, 40.2-62.7) in 2010 (P = 0.549). Patients stayed in hospital for more than one night after 10.5% (95% CI, 6.9-14.1) of operations. Use of phacoemulsification and topical anaesthesia increased the prevalence of outpatient surgery and decreased intraoperative complications. Although outpatient cataract surgery increased by 11.7%, use of methods such as phacoemulsification is not widespread, and more attention should be paid to the barriers to outpatient cataract surgery in the Islamic Republic of Iran.