Aim: Pupillary miosis during cataract surgery and irrigation and aspiration (I/A) is found to be a major cause of iris trauma, cortex retention, posterior capsule rent, vitreous loss, and even posterior nucleus dislocation. Adequate mydriasis is necessary for safe cataract surgery. Intracameral adrenaline bolus injection can help maintain mydriasis. We designed a prospective interventional study to assess the efficacy and safety of intracameral adrenaline bolus injection after nucleus delivery, as an adjunctive to preoperative topical mydriatics. Methods: Forty patients with cataract were divided into two groups: Study group and the control group. The study group (20 patients) received intracameral bolus preservative-free adrenaline injection in the dose of 0.1 cc of 1:5000 concentration after nucleus delivery. The diameter of the pupil was measured by surgical calipers before and after nucleus delivery, after injection of intracameral adrenaline in the study group and after IOL placement in both the groups. Pulse rate, systolic, and diastolic pressure were measured before and after the cataract surgery. Results: The mean pupil size in the study group after nucleus delivery was 5.33mm and 5.32mm??in the control group. A significant pupillary dilatation was observed in the study group 30 seconds after the injection of bolus dose of intracameral adrenaline. The mydriasis obtained in the study group (mean 7.67mm??) was significantly greater than the control group mean (p__ampersandsignlt;0.0001). The mean pupil size after IOL dialing was 6.86 mm ?in the study group which was significantly greater than the control group(mean 4.20mm). The mydriasis maintained in the study group was significantly greater than the control group (p__ampersandsignlt;0.0001). Pulse rate and blood pressure showed no significant changes during the surgery in both the groups. Conclusion: We concluded that intracameral preservative-free adrenaline bolus injection (0.1cc of 1:5000) is a safe and effective adjunctive to topical mydriatics in maintaining mydriasis during surgery.