A field experiment was conducted at Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, West Bengal, India in Kharif season of 2016 and 2017 to evaluate the phytotoxicity of glufosinate ammonium 13.5% SL (15% w/v) on cotton and soil micro-flora and their consequent effects on crop growth, yield and economics. Findings depicted that there were no phytotoxic symptoms on cotton and there was better recovery of soil micro-flora population with the application of glufosinate ammonium 13.5% SL (15% w/v) 450 g/ha, resulting in maximum growth, yield and economic profitability of cotton. However, prominent toxic effects of glufosinate ammonium 13.5% SL (15% w/v) on the crop and soil micro-flora were recorded at higher doses of 900 g/ha and 1800       g/ha, which significantly reduced cotton growth, yield and economic viability.