Intraoperative floppy iris syndrome (IFIS) is charcterised by flaccid iris stroma leading to fluttering and billowing of iris, tendency of iris to prolapse through surgical incisions and causing intraoperative pupil constriction. IFIS is characterised as complete when all three features are present, or incomplete in the absence of any feature. Potential complications associated with IFIS include posterior capsule rupture, vitreous loss, iris prolapse, iris stromal atrophy, capsular tear and anterior chamber haemorrhage resulting from a restricted surgical field secondary to miosis. In this prospective study the authors evaluated the risk factors for (IFIS) in patients undergoing phacoemulsification. Included in the study were 1274 consecutive Caucasian patients, who underwent routine phacoemulsification cataract surgery. Data included ophthalmological conditions, axial length of the eye, sociodemographic features, clinical data (hypertension and diabetes mellitus), medications being taken at the time of surgery, and duration of their intake. The patients were dilated with tropicamide 0.5% and phenylephrine hydrochloride 5% and routine phacoemulsification surgery was performed. Intracameral alpha agonists were not administered. Univariate and multivariate logistic regression analysis were performed. IFIS was observed in 63/1274 eyes (4.9%, 95% CI: 3.9-6.7%). Cases were characterised intraoperatively as IFIS and non-IFIS using the criterion of Chang and Campbell. Out of the 63 patients with IFIS 41 presented with complete IFIS and 22 incomplete IFIS. Apart from the well-established associations with α-blockers, this prospective study points to benzodiazepines, quetiapine, finasteride and hypertension as potential risk factors for IFIS. Short axial length and rivastigmine were significantly associated with IFIS only at the univariate analysis. The study adds to our current understanding of IFIS and its risk factors. It may further help in appropriate delivery of pre-op patient information and also help in minimising and prevention of potential surgical complications.