A field experiment was conducted on sandy clay loam soil at Kathalagere, University of Agricultural Sciences, Bangalore (Bhadra command area of southern transition zone of Karnataka) during 1999 to 2006 in lowland transplanted rice -rice cropping system to know the effect of continuous use of weed management practices on weed shift and yields. Use of herbicide butachlor 0.75 kg + 2,4-D EE 0.4 kg/ha at three days after application (DAP), applied in sequence gave broad spectrum weed control during kharif but its application during summer could not lower the density of sedge and grasses and consequently gave slightly lower yield by 15^th season (5055 kg/ha) than rice treated with butachlor + 2,4-D EE in kharif and pretilachlor 0.75 kg/ha in summer (5446 kg/ha) and farmers’ practice of hand weeding twice (5101 kg/ha). Further, continuous use of butachlor 0.75 kg + 2, 4-D EE 0.4 kg/ha at 3 DAP both during kharif and summer paved way for dominance of sedges (particularly C. difformis and F. miliacea) and grasses (E. glabrascens) during fourth summer crop of rice–rice system, as compared to the use of butachlor 0.75 kg + 2, 4-D EE 0.4 kg/ha at 3 DAP during kharif followed by pretilachlor 0.75 kg/ha during summer. Thus, rotation of butachlor + 2, 4-D EE followed by pretilachlor lowered the menace of sedges, grasses and broad leaf weeds in long term rice- rice system. Continuous use of herbicides gave rice yields (4637 to 4768 kg/ha) similar to hand weeding (4856 kg/ha) and saved weeding cost considerably. Combined use of fertilizers and FYM did not favour any weed types, density or dry weight as compared to fertilizer usage alone