To assess the results of posterior neodymium:YAG (Nd:YAG) laser capsulotomy in patients with late postoperative capsular block syndrome (CBS) with decreased vision because of posterior capsule opacification (PCO). Baskent University Hospital, Department of Ophthalmology, Ankara, Turkey. Case-control study. Patients with CBS who had phacoemulsification and foldable hydrophilic or hydrophobic acrylic intraocular lens implantation with continuous curvilinear capsulorhexis were retrospectively reviewed. Transparent to slight milky fluid had collected in the capsular bag. Capsular block syndrome was undiagnosed before the PCO developed. The CBS was treated with Nd:YAG laser capsulotomy, after which the change in refraction, corrected distance visual acuity (CDVA), intraocular pressure (IOP), complications, and inflammation rate were evaluated. Follow-up examinations were at 1 day, 1 week, and 1 and 6 months. The mean time between cataract surgery and laser capsulotomy was 48 months ± 10.27 (SD) (range 28 to 66 months). The Nd:YAG capsulotomy was successful in all eyes. Capsulotomy did not change the refraction in 14 eyes (93.3%). One patient (6.6%) had a change of +0.75 diopter. After capsulotomy, the logMAR CDVA improved in 13 cases (mean 0.26 ± 0.18; range 0.0 to 0.7) and did not change in 2 cases. There were no complications, inflammation, or significant IOP changes. Neodymium:YAG laser capsulotomy in patients with PCO associated with late CBS increased visual acuity without a significant change in refraction or IOP. Capsular block syndrome may be asymptomatic and remain undiagnosed for a long time after cataract surgery before PCO develops.