A study was undertaken in the established benchmark soil series in different agro-ecological sub-regions of Black Soil Regions of India with the objective to assess the urease activity as a function of soil depth, bio-climate, cropping system and land use type. The urease activity declined with increase in soil depth. Maximum activity was restricted within 0–30 cm of soil depth. Cropping systems and bio-climates significantly (p sub-humid (dry) > semi-arid (dry) > arid. The activity in different cropping systems was in decreasing order viz.