Background: With the expansion of the restaurant industry and the increased consumption of fast food, the hygiene of food ingredients and the quality of oils used in the frying process have gained significant importance. This article explores the levels of peroxides and polar compounds in edible oils used in fast food establishments in Noorabad city. Methods: Twenty-seven units were selected using the Cochran formula. Sampling from the selected units was conducted in two stages periodically on non-holiday days. The collected samples were transferred to the laboratory and analyzed according to the Iranian Industrial Standards and Research Institute Standard 4179. The collected data were analyzed using SPSS software, ANOVA, and post-hoc tests. Results: In the first sampling stage, 40.7% of the samples, and in the second stage, 29.6% exceeded the permissible limits for polar compounds. Significant correlations were found between the production of polar compounds, temperature, time, and the type of container used (p < 0.05). The amount of polar compounds increased with the use of oil for more than 20 minutes, with cast iron containers having the most significant impact compared to copper and aluminum containers. Additionally, significant differences were observed in peroxide production based on the type of container, time, and brand used (p < 0.05), with cast iron having the least impact Conclusion: Based on the obtained results, it can be concluded that the duration of oil usage, the type of container, and the brand used significantly affect the quality of oils used in fast food establishments. This information can contribute to improving processes and hygiene standards in these units, ultimately ensuring consumer health.