We studied intraocular pressure (IOP) changes and specular microscopic findings in 118 consecutive neodymium-YAG laser posterior capsulotomy procedures; 37 cases were aphakic, and 81 were pseudophakic. There was a significantly greater rise in IOP one hour after Nd-YAG laser treatment in the aphakic group than in the pseudophakic group (8.2 mm Hg vs 3.5 mm Hg, respectively). At one week postoperatively, IOPs in the aphakic group were still significantly elevated over baseline levels (3.6 mm Hg), while those in the pseudophakic group had returned to baseline levels. Differences in treatment between the aphakic and pseudophakic groups in total number of pulses, average energy, and total energy did not explain the differences in IOP. No significant change in endothelial cell densities was seen between pretreatment measurements and those taken one week after Nd-YAG laser treatment.