A field experiment was conducted to examine the efficacy of different herbicides for controlling weeds in onion (Allium cepa L.) during rabi 2012 and 2013. The experiment was laid out in randomized complete block design with different weed management practices viz. alachlor @ 1.25 kg ha-1, oxyfluorfen @ 0.25 kg ha-1, quizolofop ethyl @0.05 kg ha-1, pendimethalin @ 0.75 ha-1, pendimethalin@ 0.75 kg ha-1+ one hand weeding (30 DAT), two hand weddings (30 and 60 days after transplanting (DAT) and control (unweeded). Application of all the herbicides caused a significant reduction in the weed population and weed dry matter over unweeded control in both the years of investigation. The parameters that significantly affected by different herbicides were bulb weight, bulb diameter and onion bulb yield. Application of pendimethalin @ 0.75 kg a.i ha-1 + one HW (30 DAT) gave the highest bulb yield which was at par with two and weedings (30 and 60 DAT). The highest net returns of Rs 194.2 × 103 ha-1 with B : C ratio 2.72 was obtained in the pendimethalin @ 0.75 kg ha-1+ one HW (30 DAT) followed by two hand weedings (30 and 60 DAT). Unweeded control treatment recorded lowest net returns of Rs 112.4 × 103 ha-1 with benefit: cost ratio 1.64.