Oyster mushroom (Pleurotus ostreatus) is the second most cultivated edible mushrooms worldwide after Agaricus bisporus and has more economic, ecological values and medicinal properties. Huge amounts of ligno-cellulosic agricultural crop residues by-products rich in organic compounds are annually generated. This study was conducted to compare effects of different agro residues on growth and bioconversion efficiency of oyster mushroom. P. ostreatus was cultivated on different treatment substrates viz., corn sheath+ corn cob+ coir pith (T1), paddy straw+ ragi straw (T2) and sugarcane bagasse (T3) supplemented with 10% wheat bran. Parameters such as spawn run days, primordia formation (days), harvest days, total yield and biological efficiency were evaluated. The best substrate was found to be T2 (paddy straw+ ragi straw) in terms of spawn run (28 days), primordia formation (30 days), average number of fruiting bodies (108±1.3), stem length (7 cm) and cap diameter (9.5±0.085 cm). Total yield of P. ostreatus on different treatment substrates T1, T2 and T3 was found as 507±5 g, 317.7±3.1 g and 761±7.5 g, respectively. The biological efficiency of P. ostreatus was found high in T2 (92.08±0.89%) followed by T3 (87.39±0.85%) and T1 (72.37±0.7%).