Abstract: Field experiments were conducted during Kharif 2000 and 2001 in the wetland research farm of Tamil Nadu Agricultural University, Coimbatore to study the effects of green manuring and fertilizer N application based on LCC grades on the yield enhancement, nutrient uptake and economics of hybrid rice. Treatments consisted of two hybrids in the main plot and seven levels of N management practices during Kharif 2000 and eight sub-plot treatments during Kharif 2001. Among the hybrids, PA6201 registered significantly higher grain yield of 7363 and 7555 kg ha-1 during Kharif 2000 and 2001 respectively with a yield advantage of 9.5% over CoRH2 in both the seasons. The N, P and K uptake at different growth stages revealed that rice hybrid PA 6201 was superior than CoRH2 in both the seasons. Application of green manure @ 6.25 t ha-1 in combination with N application based on LCC critical value 5 recorded significantly higher grain yield compared to other treatments in both the seasons. The N, P and K uptake in green manure @ 6.25 t ha-1 combined with LCC critical value 5 based N application (N4) was significant at all the stages, however it was comparable with 200 kg N ha-1 alone (N1) except at tillering stage. In both the years PA6201 hybrid recorded high net returns of 15.05 and 14.60% over CoRH2. Application of green manure @ 6.25 t ha-1 combined with LCC critical value 5 based N application (N4) recorded higher net returns and B:C ratio during both the years and it was followed by application of 200 kg N ha-1 alone (N1). Therefore, the rice hybrid PA6201 with application of green manure 6.25 t ha-1 combined with LCC critical value 5 based N applications significantly increased grain yield, nutrient uptake and in turn resulted in higher net return and B:C ratio.