This study examines the mass loss patterns and meso-invertebrate populations during rice and sorghum straw decomposition, using litter-bag technique, in an agricultural system at Kurukshetra (29°58’N, 76°51’E, 250 m above mean sea level). The decomposition rates were influenced by litter quality, soil and litter moisture, leaching of water soluble substances, and colonization by the meso-invertebrates. During the cropping season, wet soil conditions favoured rapid decomposition rates. For the total sampling period of 285 days, the mass loss of rice and sorghum straw was 78·2 and 82% respectively. The single exponential model described the pattern of decomposition over time (r2=0·88,Ps0·001). Meso-invertebrate populations were higher during rapid phase of decomposition and influenced by soil and litter moisture. Maximum meso-invertebrate density per litter bag was 77·4±6·12, for rice straw and 78·4±3·05 for sorghum straw. Collembola and mites were the dominant groups of fauna in litter bags. Enchytraeids formed 2·45% of the total meso-invertebrates extracted from litter bags.