Five patients who underwent uneventful cataract extraction developed flat anterior chamber (AC) secondary to pupillary block, 2 1/2 to 4 weeks postoperatively. None had a wound leak. After drug therapy had failed to restore the AC, iris photocoagulation was performed. Four eyes were treated with a xenon-arc photocoagulator, and one with both a portable xenon-arc unit and an argon laser. The AC deepened immediately and permanently in all cases. No complications occurred, and visual acuity was good. Iris photocoagulation with a xenon-arc unit is a valid alternative to intraocular surgery in therapy for flat AC that is caused by aphakic pupillary block in patients in whom medicinal therapy fails and no wound leak is present.