A field experiment was conducted during rainy seasons in 2011 and 2012 to study the efficacy of pre- and post-emergence herbicides on weeds, growth, symbiotic traits and grain yield of greengram. Pre-emergence application of pre-mix pendimethalin + imazethapyr at 1.0 kg/ha showed lowest weed index and highest weed control efficiency, followed by pre-mix pendimethalin + imazethapyr at 0.75 kg/ha and two hand weedings done at 20 and 40 days after sowing. Post-emergence application of quizalofop-ethyl at 37.5 g/ha reduced the number and dry weight of nodules/plant compared to other herbicides. Weed free treatment provided the highest grain yield, gross returns and net returns. Among the herbicides, pre-emergence application of pre-mix pendimethalin + imazethapyr at 1.0 and 0.75 kg/ha recorded higher grain yield (1.41 and 1.31 t/ha, respectively) and provided higher net returns (` 52970 and ` 48390, respectively) and B:C ratio (2.57 and 2.44, respectively) than the other treatments of herbicides due to significant reduction in the dry weight of weeds and higher weed control efficiency and consequently improving the yield attributing parameters.