BACKGROUND: Diabetes mellitus is a syndrome characterized by chronic hyperglycemia, due to absolute or relative deficiency or diminished effectiveness of circulating insulin. A diabetic diet simply means, eating the healthiest food in moderate amounts at regular mealtimes. Objective: The objective of this study was to assess knowledge, attitude, practice and associated factors among diabetic patients on diabetic diet at Felege hiwot referral hospital in Bahir Dar, Northwest Ethiopia. Methods: Institution based cross sectional quantitative study was conducted from February 4 to April 4, 2019 at Felege hiwot referral hospital, Bahir Dar, Ethiopia. Data were collected by using structured questionnaire. Logistic regression analyses were used to analyze the quantitative data. In the logistic regression, both bivariate and multivariate analysis were used to list out factors associated with diabetic diet. Those independent variables at P– Value of < 0.2 in the bivariate analysis were invited to the multivariate analysis. Results: A total of 410 diabetes patients who have follow up at the hospital were included. Among this, 58.8% and 41.2% had good and poor knowledge about diabetic diet respectively 49% and 51% was positive attitude and negative attitude about diabetic diet respectively and 58.3% and 41.7% was good practice and poor practice about diabetic diet respectively. The independent factor which showed significant associations for knowledge on diabetic diet were nutritional education in the hospital (AOR=2.6, CI=1.6-4.2), marital status widowed (AOR=7.3, CI=3.8-14), place of residence (AOR= 2.9, CI=1.7-4.8) and enough information about food planning to control your DM (AOR=2.5, CI= 1.5-4). The independent factor which showed significant associations for attitude on diabetic diet were age between 18-32yrs (AOR=8.7 ,CI=3.1-24.6),age between 33-41yrs(AOR=4.0,CI=2.2-7.2),age between 42-50yrs(AOR= 1.8, CI=1.0-3.2),educational status those are uneducated (AOR =4.4,CI= 2.4-7.9), able to read and write (AOR= 8.3 ,CI=3.6-19.0), primer school (AOR= 4.8 ,CI =2.0-11.4), secondary school (AOR= 3.2 ,CI=1.64-6.6),nutritional education (AOR= 2.55 CI= 1.5-4.1).