Red chilli was irradiated with two types of radiations; gamma and microwave. The effects were evaluated in the changes in the capsaicin concentration, and the volatile oil composition through the methods: micellar electrokinetic chromatography and gas chromatography/mass spectrophotometry (GC/MS). Gamma irradiation used at a dose of 10 kGy. Microwave radiation was performed by continues supply of 50 W/Kg of red chilli for 15 min. Capsaicin decreased 63.17% by gamma irradiation and 21.29% by microwave treatment. Forty-four volatile oils have been identified, most of them reported for the first time. The total amount was 898 mg/kg and decreased by irradiation: 566 mg/kg and after microwave: 524 mg/kg. Some aromatic hydrocarbons such as heptadecane, tetramethylhexadecane and octadecane were disappeared completely after both treatments. Other organic compounds like ethyl benzene persisted in the same level after treatments. The precision and accuracy was investigated by standard deviation for reproducible measurements and recovery, respectively. Statistical analysis was performed by using Student's t-test. Differences were considered significant at P ≤ 0.05. Keywords: Red chilli, Gamma, Microwave, Capsaicin, Volatile oil