In this study, it was investigated the effect of microwave heating on oil yield, total phenolic content, antioxidant activity, phenolic compounds of cashew nut and also fatty acid composition of cashew nut oil. The oil content of cashew nut heated in microwave oven increased, especially heated at 720 W (44.43%). Generally, the antioxidant activity and total phenolic contents of cashew nut extracts decreased with heating process. However, the highest antioxidant activity (52.80%) and total phenolic content (107.00 mg/100 g) were observed in cashew nut extracts heated at 720 W. The key phenolic compounds of cashew nut were 1,2-dihydroxybenzene (16.57–70.03 mg/100 g), (+)-catechin (17.50–52.81 mg/100 g) and gallic acid (12.53–51.51 mg/100 g). In addition, the main fatty acids of cashew nut oil were oleic (59.59–61.82%), linoleic (18.20–26.28%), palmitic (7.16–9.23%) and stearic (4.07–9.49%) acids. Both phenolic compounds and fatty acid compositions of cashew nut showed a significant changes at 720 W.