Diabetes eye complications, and particularly diabetic retinopathy, are the major cause of blindness in the working age groups of industrialised countries. Laser photocoagulation has been proven to reduce blindness due to retinopathy by at least 60% but even more patients would benefit if treatment were delivered at an early enough stage. High risk retinopathy, though, does not cause visual symptoms and when the latter occur it is often too late to reverse them. Hence, a screening programme for diabetic retinopathy should aim at detecting patients at risk when they can still be effectively treated. This can be obtained by regularly checking the patients' eyes. Its target, as defined by the joint World Health Organisation/International Diabetes Federation Saint Vincent Declaration Working Group, is to reduce diabetes-related blindness by one third or more in the next 5 years. The number of persons to be screened is high, 30,000/million total population/year, but available data indicate that this is feasible and that the initial investments in professional and material resources are more than justified by the reduction of preventable blindness and of the financial burdens that go with it. Indeed, prevention of the major cause of blindness in the working age should rate the same priority as other widely deployed programmes, such as those to screen for cancer, neonatal hypothyroidism and phenylketonuria. The concerted action of government health departments, patients' and professional associations will be vital for the successful implementation of this programme. The texts of this document (a protocol for the screening of diabetic retinopathy and cataract), Appendix 1 (data collection card) and Appendix 2 (informative leaflet for the patients) were approved by 57 specialists, representing 30 diabetic and ophthalmic societies from 21 European countries, and endorsed for translation into all European languages and distribution at the appropriate levels.