A long-term follow-up study was carried out on 159 cases (245 eyes) of pre-proliferative and proliferative diabetic retinopathy. In 75 percent of the series, diabetic retinopathy progressed and visual acuity markedly decreased. Argon Iaser panretinal photocoagulation was performed and followed-up in 80 of the cases (138 eyes). 50.72% of these obtained good results, visual acuity improved by more than 2 lines. Only 10.14% of the treated series showed progression of the disorder. There were 10 cases of diabetic mellitus associated with pregnancy. Argon laser panretinal photocoagulation just prior to and after delivery was effective against preproliferative and proliferative diabetic retinopathy. The prognosis of pregnant patients was greatly enhanced.