Introduction: Ready-to-use products are designed to be consumed directly and do not require preparation. These include lipid-based nutrient supplements and ready-to-eat biscuits. These products can be divided into two groups: Ready to-use therapeutic foods (RUTFs) and Ready-to-use supplementary foods. Objective: The aim of this study was to assess acceptability of ready to use food and associated factors of ready to use Food among adult ART clients in Felegehiwot Referral Hospital, 2016. Method: Institutional based cross sectional study was carried out on ready to use food treatment center on 422 randomly selected malnourished adult HIV patients at Felegehiwot Referral Hospital from October 1 to November 30 2016. The data was coded and entered to SPSS version 21 for analysis and the data was presented by tables, frequencies and factors associated with acceptability was done using regression analysis and variables with p value <0.05 was considered as statistically significant. Result: Of the total of 420 ready to use food (RUF) study participants, 294 (70%) accepted RUF completely and 126(30%) had refused either because of the unpleasant taste, smell unattractive color or consistency. About 96% of the participants accepted the taste and 84% accepted the smell and 64.8% reported with no side effects associated with ready to use food (RUF) taking. This finding showed that, who know their duration of treatment showed significant difference in acceptability compared with that did not know their duration of treatment. Conclusion and recommendation: In conclusion there should be adherence counseling on ready to use food advantage in order to increase its acceptability on people living with HIV. Keywords