A field experiment was conducted to study the effect of three nitrogen levels and weed management practices on grain yield of aerobic rice at Tamil Nadu Rice Research Institute, Aduthurai during Kharif seasons of 2014 and 2015. The main plot treatments comprised of three nitrogen levels (75, 100 and 125 kg/ha N) and sub-plot treatments consisted five weed management treatments, viz. rice + Sesbania (dhaincha) (1:1) + pendimethalin pre-emergence application (PE) at 1.0 kg/ha followed by (fb) one hand weeding at 60 days after sowing (DAS); pendimethalin 1.0 kg/ha PE fb mechanical weeding twice at 20 and 40 DAS; rice + Sesbania (dhaincha) (1:1) + pendimethalin 1.0 kg/ha PE fb 2,4 D Na salt 0.8 kg/ha post-emergence application (PoE); mechanical weeding twice at 20 and 40 DAS and un-weeded control. The Rice + Dhaincha (1:1) + pendimethalin PE fb 2,4 D Na salt PoE recorded the lowest weed density at 20 DAS. At 40 and 60 DAS, pendimethalin PE fb mechanical weeding twice at 20 and 40 DAS recorded lower weed density and biomass during both the years. Among the N levels, application of N at 125 kg/ha resulted in maximum rice plant height, number of tillers/m2, number of panicles/m2, panicle weight and grain yield, during both the years. Pendimethalin PE fb mechanical weeding twice at 20 and 40 DAS resulted in higher rice plant height, number of tillers/m2, number of panicles/m2, panicle weight and grain yield. Application of N at 125 kg/ha along with pendimethalin PE fb mechanical weeding twice at 20 and 40 DAS may be used for effective weed management and higher productivity of aerobic rice.