A field experiment was conducted at Central Research Farm, Gayeshpur, Nadia, West Bengal, India during the Kharif (rainy) seasons of 2019-20 and 2020-21 to evaluate bio-efficacy and phytotoxicity of herbicide pretilachlor 50% EC in transplanted rice and its residual effect on utera/paira (follow up) crop lathyrus. The experiment was placed in randomized complete block design comprising 10 treatments (pretilachlor 50% EC 375, 500, 625, 750, 875 g/ha, pendimethalin 30% EC 1000, 1500 g/ha, Butachlor 50% EC 1250 g/ha, hand weeding at 15 and 30 days after transplanting and unweeded control) and replicated thrice. Pooled results revealed that application of pretilachlor 50% EC 625 g/ha was superior over pendimethalin and butachlor remained equally effective as hand weeding in ensuring high weed control efficiency. Consequently, 4.38 and 4.98 t/ha of grains and straw yields, respectively were obtained at pretilachlor 50% EC 625 g/ha. Further, no phytotoxic effect on crop as well as on soil health was observed under application of that herbicide. Performance of paira crop lathyrus did not get hampered due to herbicidal applications in rice due to dissipation of toxicity from soil. Therefore, early post-emergence application of pretilachlor 50% EC 625 g/ha can be safely recommended for transplanted Kharif rice cultivation in Gangetic plains of West Bengal.