Introduction: Diabetic retinopathy is becoming an increasingly important cause of visual impairment in India. Many diabetic patients who come to our centre have undetected, advanced diabetic retinopathy. If diabetic retinopathy had been detected earlier in these patients, irreversible visual impairment could have been prevented. Aim:To document Knowledge, Attitude and Practice (KAP) patterns of diabetic patients regarding diabetes and diabetic retinopathy, to determine association between them, and to identify barriers to compliance with follow up and treatment regimes. Materials and Methods:This was a hospital-based, cross-sectional study, conducted at the Department of Ophthalmology at Christian Medical College, Vellore, Tamil Nadu, India, over a six-month period from June 2013 to November 2013. Two hundred and eighty eight diabetic patients, who fulfilled the eligibility criteria, were included in the study. KAP of patients was assessed using a 45-point, verbally administered questionnaire. Patients were placed in different categories, such as, 'good/ poor' knowledge, 'positive/negative' attitude and 'good/poor' practice. Data were analysed using Chi-square test and binary logistic regression, as appropriate. The proportion of patients with 'good/poor' knowledge, 'positive/negative' attitude and 'good/poor' practice, and the association between KAP were studied. Barriers to compliance with follow up/treatment regimes were identified. Results:Out of the 288 patients in the study, 42% had good knowledge about diabetes, but only 4.5% had good knowledge about retinopathy. Good knowledge about diabetes was significantly associated with positive attitude towards diabetes and good practice patterns regarding retinopathy; awareness of retinopathy was also significantly associated with good practice. A total of 61.1% of patients did not have periodic eye examination; most common barrier identified was lack of awareness about the necessity for this (38.5%). Conclusion:Good knowledge about the disease was significantly associated with positive attitude and good practice patterns. Knowledge about diabetic retinopathy was poor among the patients in our study. Lack of awareness concerning the need for screening for retinopathy was a major barrier to regular screening. There is an urgent need to educate diabetic patients about this potentially blinding complication of diabetes.