Field experiments were carried out in wetland farm at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu during 2012-13 to study the weed density, weed seed bank, yield and economics of rice under rice based conservation agriculture system. The main plot consisted six treatments with two crop establishment methods and three tillage practices over the seasons. Sub-plot treatments were having three weed management practices. Significantly minimum total weed density, weed seed count and higher grain yield, net returns were recorded in transplanted rice with conventional tillage in CT-CT-ZT system with pre-emergence treatment (PE) of butachlor 1.0 kg/ha for Kharif, pretilachlor 1.0 kg/ha PE for Rabi + inter crop with daincha (Sesbania) incorporation and mechanical weeding on 35 DAT during Kharif 2012, Rabi 2012-13 and Kharif 2013.