A field experiment was conducted during rainy season of 2008 to study the effect of fertilizer and manure on weed incidence and depletion of nutrients by weeds in soybean. The relative density (RD) of broad leaved weeds were found dominant (33.63%) among all other weeds. Commelina communis was 14.68%, Echinochloa colona 11.97%, Cyperus rotundus 10.14%, Cynodon dactylon 6.70% and other weeds 22.86%. Among the different fertility levels, 100% NPK (20:80:20) + 15 t FYM/ha gave significantly lowest weed biomass, highest WCE (61.51%), zero percent weed index, significantly highest grain yield (8.13 q/ha), highest NPKS nutrient contents in weeds and lowest depletion of NPKS nutrient by weeds