Background: Ethiopia is one of the top five countries with largest number of people affected by DM, the highest prevalence of type-2 DM was found in Addis Ababa (15.8%). Nutrition knowledge and Dietary modifications are the cornerstones of type 2 diabetes management. There is limited study about the Nutritional knowledge and dietary Adherence of type 2 DM patients in the study area. Objective: This study was aimed to assess nutritional knowledge, adherence to dietary recommendation and associated factors among adult type 2 diabetes mellitus patient in public health centers, Addis Ababa, Ethiopia. Method: Facility based cross-sectional study was conducted. The sample size was calculated by using single population proportion formula, Analyses was done by SPSS version 23. Result: The study achieved participants fully completed questioner with 100% Response rate. Majority of respondents (73.9%) were age greater than or equal to 45 years, Female accounts 55% of the total study participants. Of 422 respondents, 224 (53%) type2DM had good nutrition knowledge and 231(55%) were adhered to dietary recommendations. participants who were Illiterate AOR=1.342, 95%CI: (1.062, 1.696) and create awareness about recommended diet for their families (AOR = 0.517, 95% CI: 0.282-0.946) were significantly associated with nutritional knowledge. And income (AOR=0.683, 95%CI 0.476-0.979), Occupation (AOR=0.684(0.534-0.877), Family Support (AOR=0399, 95%CI, 0.243-0.655), Controlled Blood glucose level in past 3 month (AOR= 0.202, 95%CI, 0.142-0.288) were significantly associated with dietary adherence. Conclusion: Closer to 50% of DM patient had poor nutritional knowledge and 45% of them had poor adherence to dietary recommendation, more over only 28.4 had controlled blood glucose. Illiteracy and not getting dietary awareness were significant barriers for poor nutritional knowledge. Similarly income level, occupation, family support, family history of DM, dietary education from health professionals and blood glucose control were the most influencing factors for poor Adherence. So Attention should be given to address these barriers and improve glycemic control. Key words: Nutritional knowledge, Adherence, Recommended diet, Diabetes Mellitus