The incidence of focal and panretinal photocoagulation and its relationship to demographic and other characteristics were examined in a population-based study of people with diabetes in southern Wisconsin. For participants whose age at diagnosis was less than 30 years, who were taking insulin, and who had not been previously treated with photocoagulation, the 4 year incidence of panretinal photocoagulation (10.8%) was significantly higher ( p<.0001) than the rate of focal and/or grid photocoagulation of the macula (4.3%). For those whose age at diagnosis was 30 years or older and who had not been previously treated with photocoagulation, the incidence rates of panretinal photocoagulation (4.4%) and focal and/or grid photocoagulation of the macula (3.1%) were not significantly different ( p=.11). At follow-up examination, 33.8% of the eyes of younger onset persons and 57.7% of the eyes of older onset persons with Diabetic Retinopathy Study high risk characteristics for severe visual loss had never received panretinal photocoagulation. These relatively high frequencies of untreated eyes in need of panretinal photocoagulation remain a concern.