We evaluated tele-ophthalmology for diabetic retinopathy screening in a primary care setting. Four general practitioners (GPs) were taught to assess non-mydriatic retinography images of patients with diabetes. After training, a total of 1223 patients were screened using this method: 926 (76%) did not have diabetic retinopathy and 297 (24%) were referred for an ophthalmologic assessment. Of the 297 patients, 186 (15%) did not have diabetic retinopathy and were considered to be false positives, 85 (7%) had diabetic retinopathy and in 26 cases (2%) the retinography images were unreadable. The specificity of GPs for detecting diabetic retinopathy by non-mydriatic retinography was 83%. Ophthalmologists also assessed 120 patients who had been diagnosed as normal to detect false negatives. Ten patients (8.3%) had mild non-proliferative diabetic retinopathy with small isolated retinal hemorrhages. Only one patient (0.8%) had treatable diabetic retinopathy with hard exudates and microaneurysms. The sensitivity of GPs for detecting diabetic retinopathy was 90.9%; the sensitivity for detecting treatable lesions was 99.2%. We concluded that adequately trained GPs can screen for treatable lesions of diabetic retinopathy with a very high level of reliability using non-mydriatic retinography.