The authors reviewed the preoperative, postoperative, and follow-up examinations, fundus photographs, and fluorescein angiograms of 175 eyes with proliferative diabetic retinopathy treated with panretinal photocoagulation. Seventy-five (43%) of the treated eyes developed increased macular edema 6-10 weeks following laser treatment. Follow-ups ranged from 3 months to 48 months, with a median follow-up of 15 months. Fluorescein angiography revealed that the postlaser increase in macular edema persisted in 47 of the 175 eyes (27%). Fourteen eyes (8%) treated with laser developed chronic macular edema and visual loss of two or more lines. Inflammation and altered retinal blood flow are possible pathogenetic mechanisms responsible for the development of postpanretinal photocoagulation macular edema.