The frying oil gets altered with the use of it, and it should be controlled to avoid foreign compounds get involve in food and future consumers. It have been identify that oil used in potatoes’ frying for 16 days (275 fries), and pork frying for 6 days (60 fries); evaluating organoleptic changes (shape, color, smell, taste and consistency) and physics chemicals (Humidity, refraction index, acidity, and peroxides). The potatoes frying oil shows acceptable characteristics without indicators of acidity or peroxides that will contribute a risk to the food quality, or to the consumer health. The meat frying oil shows unacceptable organoleptic changes, without reaching unacceptable values of acidity and/or peroxides. Which means: the potatoes frying oil can be use for a longer period of time while the meat frying oil even though did not show a chemical deterioration, their organoleptic characteristics made it unacceptable to continue uses. Giving and intense color, smell and taste to the food in question