Frying oils were evaluated into two methods .Firstly the chemical evaluation, by determining  some physico- chemical characteristics namely specific gravity (SG) , acid value (AV) , Peroxide value (PV) , free fatty acids (FFA%) and fatty acids profile and results indicated that acid value of frying oils samples were 1.34 before frying and reached to  8.36 after frying  process in high grade restaurant  ,while the Peroxide value being  22.435 before frying but after frying  reached  417.39 ml eqv./kg oil Also, frying process showed a high percentage of harmful trans fatty acids in all  fried oil sample . Secondly the survey study  consists of two parts, the first part is concerned with the staff who work in fast food restaurants and the second part is concerned with the guests who usually eat some fast foods meals . Results showed that the age of the staff who worked in fast food restaurants which answered to Less than25 years ,25 to 35 years and36 – 45 more and  It's obvious that the gender was male with 100%  and the age was between 25-35 with 48.6 % and 36- 45 and more with 50 %., the reasons of using the most common frying oils in this question which answered to price , oil smell, flavor and other reasons.   We have found also,  that the gender of the people who eat fried products more than the other are equal with 46 % for males and 46 % for females .and  the age of the customers  who eat in fast food restaurants which answered to 45.7% were from 20 to 30 years and 30 to 40 and more with 37 % . Then  we have to know if there is stability in the taste of fried product that the customers eat in the restaurant and the result was 42.4 % with yes and 26.1% with no and 31.5 % with sometimes. Finally , we have to know what are the flaws that the customers have seen before in fried  food from their point of view and we have found the biggest flaw was changing the taste with 52.2 %  then changing the color with 31.5 % then 16.3 % was for the changing of the smell. So,  it's clear from the results of previous tests and questionnaires we  need to focus on the process of frying and Oil Change to avoid the formation of harmful compounds health operations especially trans fatty acids and saturated fatty acids. This research aimed to study and evaluate the quality of some frying oils which were randomly collected from some fast food restaurants three categories
 ( international, national and local ) in El-Dakahlia Governorate.