Purpose: To compare posterior capsular opacification (PCO) between a combined procedure and a sequential procedure of pars plana vitrectomy (PPV) and cataract surgery (CS). Methods: The medical records of 89 eyes of 85 patients who underwent PPV and CS were retrospectively reviewed. There were 56 eyes of 52 patients with a combined PPV and CS (the combined surgery group), and 33 eyes of 33 patients with CS in a previously vitrectomized eye (the sequential surgery group). The control group was comprised of 130 eyes of 102 patients who underwent CS alone. All patients were followed up for at least 1 year after CS. The major outcome measures were the PCO rate and the interval between CS and PCO formation. There were no significant differences in age and the incidence of diabetes among the 3 groups. Results: The PCO rate checked at 1 year after CS was 12.5% (7/56) in the combined surgery group, 24.2% (8/33) in the sequential surgery group, and 4.6% (6/130) in the control group. The differences in the PCO rate between the subgroups as well as among the 3 groups were statistically significant (p < 0.05). There were no significant differences in the interval between CS and PCO formation among the 3 groups. Conclusion: This study demonstrates that the PCO rate may be lower in patients who have a combined procedure of PPV and CS than in those who have a sequential procedure.