Urea is the major nitrogen fertilizer used in the world due to its high N content, high solubility, and nonpolarity. However, it is susceptible to various nitgrogen loss mechanisms, namely, ammonia volarilization, leaching, and denitrification. Ammonia that emanates from the urea applied to agricultural fields, contributes to acid I rain, while nitrates produced in soil contribute to contamination of ground waters due to leaching of nitrates, and ozone depletion due to release of nitrous oxide by denitrification process. Due to increasing food demand globally for increasing human population, consumption of lu ea may increase several fold hy the end of 21st century. Available data on nitrogen use efficiency indicates that one-third to one-half of the applied urea-N is lost, contributing to health and environmental hazards. An interdisciplinary effort is required for developing urea-based nitrogen fertilizers that will release nitrogen slowly resulting in efficient utilization by crop plants and thereby minimizing losses of applied nitrogen to soil and atmosphere. This will reduce the health and environmental hazards.