Purpose Sphincterotomy, an alternative to iris hooks or pupil stretching, is a technique that can aid in small pupil phacoemulsification. The incidence of post-operative complications of this procedure, however, has not been studied. Our study evaluates the post-operative outcomes of phacoemulsification surgery with adjunctive pupillary sphincterotomy. Methods We conducted a retrospective review of case notes and Medisoft (R) electronic record of patients that had undergone simultaneous sphincterotomy, phacoemulsification and intraocular lens (IOL) implantation by a single surgeon between March 2012 and February 2017. Our main outcome measures were post-operative ocular hypertension (IOP>21 mmHg), uveitis and cystoid macular oedema (CMO). Results A total of 114 eyes of 114 patients were included in this study. The mean age was 81.2 years (range: 26-100). All patients had uncomplicated surgery. Transient (<1 month) ocular hypertension developed in five (4%) eyes. Sustained ocular hypertension (>1 month) occurred in one (1%) eye, which had pre-existing glaucoma. All four (4%) eyes that developed a persistent uveitis (>1 month) resolved with topical therapy except for one eye with a history of uveitis. The 6 (5%) eyes that developed CMO had a history significant for uveitis (n = 4), diabetic macular oedema (n = 1) and epiretinal membrane (n = 1). All CMO maculae resolved to their baseline. Conclusion The incidence of post-operative complications following uncomplicated phacoemulsification and IOL implantation with pupillary sphincterotomy is low. The most important predisposing factors for development of a complication are ocular co-morbidities such as glaucoma, uveitis and the presence of a macular pathology.