Field experiments were conducted to select suitable pre- and post-emergence herbicides for the control of Trianthema portulacastrum in greengram. Treatments were consisted of pre-emergence (PE) herbicides, viz. pendimethalin (1.0 kg/ha), oxyfluorfen (100 and 200 g/ha) with one hand weeding at 30 days after sowing (DAS), post-emergence (PoE) imazethapyr 50 g/ha at 15 DAS, combinations of PE and PoE herbicides and hand weeding (HW) twice at 15 and 30 DAS and control. Significantly lesser weed density (137/m2) and dry weight (30.4 g/m2) and higher weed control efficiency (89.6%) were recorded with application of pendimethalin 1.0 kg/ha at 3 DAS + imazethapyr 50 g/ha at 30 DAS than other treatments at 45 DAS. Significantly higher dry matter production (1.34 t/ha), more number of pods per plant (38.4) and seeds per pod (9.8) were recorded with application of pendimethalin1.0       kg/ha + imazethapyr 50 g/ha 30 DAS than other treatments. Application of pendimethalin 1.0 kg/ha on 3 DAS followed by imazethapyr 50 g/ha on 30 DAS recorded significantly higher mean grain yield of 461 kg/ha, mean net returns (  14443/ha) and benefit cost ratio (2.09) over other treatments. Thus, it could be concluded that application of PE herbicide pendimethalin 1.0 kg/ha on 3 DAS followed by PoE herbicide imazethapyr 50g/ha on 30 DAS controlled the Trianthema portulacastrum effectively and produced higher productivity and profitability of greengram in irrigated condition.