Antibacterial activity of some plant extracts against Xanthomonas axonopodis pv. phaseoli (Xap) was evaluated in vitro. Xap is a Gram negative seed borne pathogen. It was found associated with seeds of lentil and caused bacterial leaf spot disease. Six plant leaf extracts (aqueous and methanolic) were evaluated in different concentrations for their antibacterial activity against Xap through disc diffusion method. Mint (Mentha piperita), black plum (Syzygium cumini) and datura (Datura metel) gave inhibition activity in both aqueous and methanolic extracts while winter cherry (Withania sominifera) showed inhibition only by methanolic extract. Three plant extracts of mint, black plum and datura also improved seed germination and controlled the pathogen on seed treatment significantly at 1%(p≥ 0.01%). Highest activity was observed in methanolic extract of mint at a concentration of 250 mg/ml showing mean inhibition zone of 12.1 mm and 12.5 mm with IA value of 440.1 mm2 and 471.0 mm2 respectively.