AIM: To assess the incidence of vitreous loss and associated risk factors in residents performing manual small-incision cataract surgery (MSICS). METHODS: The present retrospective record review study was performed on 490 patients who underwent MSICS performed between November 2018 and December 2019 by 7 third-year postgraduate residents. The study group comprised of patients having intraoperative vitreous prolapse. All the surgeries were performed under supervision of a trained assistant. RESULTS: The mean age of the participants at the time of surgery was 68.42±2.05y. Of the 490 patients, 250 patients were male, and 240 patients were female (P=0.23). A total of 215 (43.9%) eyes had mature white cataract, 185 (37.8%) eyes had brown cataract, and 90 (18.3%) eyes had immature senile cataract. The incidence of intraoperative vitreous loss among residents was 2% (10/490). Vitreous loss occurred during hydrodissection [1/10 (10%)], nucleus delivery [3/10 (30%)], irrigation and aspiration [5/10 (50%)], and intraocular lens insertion [1/10 (10%)]. Multivariate stepwise Logistic regression analysis confirmed immature senile cataract [odds ratio (OR)=3.99; P=0.02], irrigation and aspiration of cortical material (OR=3.07; P=0.03), and anterior capsular extension (OR=3.22, P=0.03) as independent risk factors for vitreous loss. CONCLUSION: Immature senile cataract, irrigation and aspiration of cortical material, and anterior capsular extension are independent risk factors for vitreous loss. Our findings may serve as a guide for future trainers or residents learning MSICS.