Pleurotus djamor var. roseus is an edible mushroom isolated from the wild and cultivated on paddy straw substrates. The present study was carried out to compare the nutritional composition and antioxidant properties of P. djamor var. roseus at different growth stages (primordia, basidiomata, and mycelia). The protein content was is in the range of 31.48 to 35.50 g/100g dw. The crude fiber content ranged from 8.0 to 14.60 g, and that of total carbohydrates ranged from 44.75 to 48.90 g. Sodium, magnesium, and calcium reached the maximum levels in basidiomata, and selenium was detected in basidiomata and mycelia (0.47 - 0.22 mg/Kg). The amino acid profile showed that all essential and nonessential amino acids and glycine showed maximum levels in basidiomata and 15.98 ± 0.01 g/100g. The fatty acid profile showed the presence of saturated and unsaturated fatty acids; the unsaturated fatty acid content was maximum in all of the samples, ranging from 76 – 40.41%. The total phenol and flavonoid contents as well as the scavenging (DPPH), ferric thiocyanate (FTC), and thiobarbituric acid (TBA) activities in the context of methanol and water extracts from primordia, basidiomata, and mycelium were determined. Among them, basidiomata and mycelial methanol extracts exhibited significant antioxidant activity. Overall, these findings show that P. djamor var. roseus can be used as a functional food for daily consumption.