Field and laboratory experiments were conducted to study the bioefficacy and residues of pre emergence herbicide pretilachlor in transplanted rice with eight treatments involving two doses of pretilachlor viz., 0.75 and 1.5 kg/ha, and with green leaf manure and gypsum as well as the farmer’s practice of two hand weeding and unweeded control. The results had indicated that the application of pretilachlor at 1.5 kg/ha fb HW registered higher weed control efficiency and numerically lower weed dry matter at all the stages. Removal of nutrients by weeds was also significantly differed with different treatments. The analysis of terminal residues of pretilachlor in rice grain, straw and post harvest soil indicated that the residues were below detectable limit.