Despite the various advantages of femtosecond laser-assisted cataract surgery (FLACS), pupillary constriction during laser photodisruption is considered one of the most unfavorable events. This study aimed to investigate the efficacy of intracameral 0.015% epinephrine injection for miosis after laser pretreatment during FLACS.A total of 82 patients who underwent FLACS for age-related cataracts were investigated in this retrospective study. The epinephrine group included patients who received intracameral epinephrine injection for miosis after femtosecond laser pretreatment, while the no-epinephrine group included the patients who underwent FLACS without intracameral epinephrine due to minimal miosis. Quantitative pupil area measurements were performed through the analysis of captured images extracted from surgical videos of both femtosecond laser pretreatment and phacoemulsification.Laser photodisruption induced miosis in both groups, although the degree of miosis was greater in the epinephrine group (4.65 ± 0.87 mm) than in the no-epinephrine group (6.30 ± 0.65 mm; P < .001). The intracameral epinephrine injection significantly increased the pupil diameter from 4.65 ± 0.87 to 5.49 ± 0.76 mm (21.61 ± 22.68%; P < .001) and the pupil area from 70.28 ± 24.46 to 96.49 ± 25.24 mm (52.89 ± 63.54%; P < .001). After additional viscomydriasis, there was no difference between groups in pupil diameter (epinephrine vs no-epinephrine group; 6.10 ± 0.77 vs 6.39 ± 0.65 mm; P = .073).A single intracameral injection of 0.015% epinephrine provided immediate and appropriate redilation of pupil in patients with significant miosis after femtosecond laser photodisruption. Intracameral epinephrine is a simple and practical option for pupil redilation in case of miosis during FLACS.