The purpose of this study was to evaluate the effect of ozone on the quality of peanut grains and crude oil extracted from these grains. Peanut samples of 1 kg were used, with a moisture content of 8.0% w.b. and stored in 3 L glass recipients. The ozonization process utilized ozone gas concentrations of 13 and 21 mg L-1, temperature of 25 °C, exposure periods of 0, 24, 48, 72 and 96 h, and a flow rate of 1.0 L min-1. Evaluation of peanut quality consisted of analysis for moisture content, electrical conductivity, lipid concentration and peanut color. The qualitative parameters of the crude oil evaluated were free fatty acids, peroxide index and iodine index. In general there was no alteration in peanut quality due to ozone, except for the coloration of the peanuts. With regard to parameters related to the crude oil extracted from the peanut, there were no qualitative alterations due to ozone exposure. It was concluded that, despite depigmentation of the skin surrounding the peanuts, the quality of the peanuts and the extracted crude oil is not affected by exposure to ozone gas at concentrations up to 21 mg L-1, for up to 96 h.