Field studies were conducted to evaluate the competing ability of weeds with different rice varieties in relation to variable plant populations. Rice variety PR 108 exhibited greater smothering effect on weeds but PR 118 obtained maximum grain yield as compared to PR 108, PR 114 and PR 116 grown under puddled transplanted conditions. The plant population of 50 plants/m2 was found to be significantly superiror to 33 and 25 plants/m2 as it recorded significantly less weed dry matter and highest grain yield compared to other population levels. Application of pretilachlor at 0.75 kg/ha as pre-emergence proved to be very effective in reducing weed dry matter and increasing grain yield upto a significant level as compared to unweeded check