Diabetic retinopathy (DR) is the most common cause of blindness in the Western world, despite the fact that blindness from DR is preventable with timely detection and retinal photocoagulation.This thesis rewiews the current knowledge of epidemiology, screening and the risk factors for the development and progression of diabetic retinopathy. A Medline search was conducted using the keywords diabetic retinopathy and risk factors. Only rewiew articles were used. The WESDR and the DCCT study showed that the most important risk factors for the development and progression of DR is hyperglycemia and the duration of diabetes. Rapid glycemic control has been associated with transient worsening of DR, however over time continued intensive glycemic control has been shown to decrease the risk of DR.Data from epidemiologic studies have shown a relationship between hypertension, hyperlipidemia, nephropathy and DR. Pregnancy is also a major risk factor for DR, but if pregnant diabetic women are well monitored and treated if necessary, very few will develop deterioration in their eye disease. Other risk factors for DR are genetic factors, anemia, ocular factors, excessive alcohol intake, socio-economic factors, and possibly smoking and hard physical exercise. The incidence and prevalence of DR of blindness is much lower in populations where screening for diabetic eye disease i established compared to populations without screening. Screening and timely treatment of DR is one of the most cost effective health procedures available. Detection of patients at risk for sight-treathening DR and photocoagulation at the right time remains one of the most important challenges within DR today.