<b>Comparative Studies on Deterioration Quality of Frying Oils used in Commercial Restaurants in Jalgaon City of Maharashtra, India</b> Deep fat frying can lead to deterioration of physical, chemical, nutritional and sensory properties of oil, which affects its frying performance. It also results in the production of volatile products such as aldehydes and non volatile fraction which remains in the frying medium. Some of these remaining products have been implicated in producing adverse health effects. Highly oxidized oils may also produce polyaromatic hydrocarbons, which have carcinogenic effect. The repeatedly frying oil samples were collected from the restaurants and fast food outlets of various types of from municipality areas of Jalgaon city and daily used oils for frying in municipality areas of Jalgaon city in amber bottles for analysis and used to evaluate the quality of these oils using standard producers. In this study, The physiochemical parameters such as Moisture, density, viscosity, AV, IV, PV, P anisidine value, totox values and TPM were used to monitor deterioration of fried oil while it was used to authenticate oil samples. In this study, the results showed that in the range of 0.05 0.34 ±0.17 , 0.9188 0.9277 ±0.35 , 33.78 44.48 ±0.03 , 0.56 4.31 ±0.53 , 80.88 115.87 ±0.16 , 8.78 13.56 ±0.87 , 9.56 14.18 ±0.69 , 29.28 41.3 ±0.38 and 10.24 20.0 ±0.26 respectively. The AV, PV and totox values which were significantly higher compared to the Codex Alimentarius Commission standards. Peroxide values of 8.78 13.56 ± 2.179 meq O2 kg deviated from the Codex standard value of 10 meq O2 kg. Acid values of 0.56 4.315±0.605 mg KOH g, which were significantly higher compared to the Codex Alimentarius Commission standards. In general, it was seen that, fast food origin waste frying oils’ viscosities, water contents and AVs were higher and iodine values were lower than those from other sectors. The densities of all the samples were generally close to each other. The results showed degradation in the physico chemical properties of the vegetable cooking oil after repetitive frying. The awareness of the general public in India regarding the usage of repeatedly heated cooking oil needs to be increased. More publicity and exposure about this little known health issue should be given in the mass media. Repeated frying oils, Moisture, AV, IV, SV, PV, P anisidine value, Totox value, human health problem 1698-1705 Issue-5 Volume-4 Shashikant Pardeshi