The study of weed dynamics in diverse cropping systems helps to formulate the strategies for effective management of weeds. Hence, this study was conducted to assess the effect of diverse cropping systems on weed dynamics and crops productivity in eastern India. The minimum total weed density (4.85 no./m2) and biomass (2.43 g/m2) during rainy season crops was recorded in fodder sorghum-mustard-blackgram systems. In winter crops, the lowest total weed density was observed in soybean-maize system (5.79 no./m2), while the lowest weed biomass (2.26 g/m2) with finger millet-rapeseed (toria) system. In summer, soybean-maize, pearl millet-chickpea and sorghum-chickpea were equally effective for reducing weed density and biomass. Weed seedbank analysis revealed maximum grass weed seed density at 0-15 cm depth in foxtail millet-lentil, while minimum with fodder sorghum-mustard-blackgram system. The highest weed seed density of broad-leaved weeds was noted at 0-15 cm depth in maize-pigeonpea and the lowest with conventionally tilled direct-seeded rice (CTDSR)-mustard-blackgram system. It was concluded that diverse cropping systems significantly suppress weed density  and biomass in all the seasons.