Purpose: The purpose of this study is to assess the knowledge of diabetic retinopathy and associated factors among adult diabetic patients at Adare General Hospital, Southern Ethiopia, Hawassa. Methods: A cross-sectional study was conducted at Adare General Hospital on 419 adult diabetic patients. Systematic random sampling was applied to select the study participants. Data were collected via a structured questionnaire, checklist, and physical examination. Binary logistics regression and descriptive statistical analyses were done using SPSS version 20. Variables having p-values of less than 0.05 were considered statistically significant. An adjusted odds ratio with a 95% Confidence Interval (CI) was used to determine the strength of association between the dependent and independent variables. Results: Among the total participants, 41.3% [95% CI (36.8-46.1)] had good knowledge about diabetic retinopathy. Urban residence [AOR=3.01, 95% CI; (1.39-6.52)], high income [AOR=4.68, [95% CI; (1.40-4.62)], type II diabetes [AOR=3.18,95% CI; (1.15-8.80)], long duration of diabetes [AOR=6.28,95% CI (3.26-12.10)], family history of diabetes [AOR=2.54, 95% CI (1.40-4.62)], history of eye disease [AOR=2.64,95% CI (1.45-4.80)] were significantly associated with knowledge on diabetic retinopathy. Conclusions: The proportion of diabetic patients with good knowledge in this study was found to be low (41.3%). Health education and promotion interventions on diabetic retinopathy and eye check-ups could enhance their knowledge and practice.