A field study was conducted at Chiplima and Sambalpur under West Central Table Land Zone of Odisha during the winter (Rabi) seasons of 2013 and 2014 to evaluate different integrated weed management practices under modified water regimes in rice grown under System of Rice Intensification. Application of 5 cm depth of  irrigation water before the day of weeding operation was effective in increasing  yield significantly (4.72 t/ha) over saturation moisture regime (3.48 t/ha) due to low weed density, weed dry weight and highest number of ear bearing tillers per plant (24) and filled grains/panicle (72). Out of four levels of different weed management systems tested, the application of pretilachlor 750 g/ha (pre-emergence) fb chlorimuron-ethyl + metsulfuron-methyl 4 g/ha (post-emergence) recorded minimum weed density and weed dry weight, higher weed control efficiency and significantly higher grain yield of 5.45 t/ha. The same treatment also recorded highest net return ( 41, 441/ha) and highest B: C ratio (2.17).