Nowadays, the application and search of alternative cheap and ecofriendly adsorbents to replace activated carbon was made. It has been a major focus for the removal of dyes from waste water. In this study untreated Parthenium hystrophorous weed (PHW) was used to remove a textile dye (Methylene Blue (MB)) from an aqueous solution by adsorption technique. The factors influencing the adsorption were also investigated. The MB dye removal by the PHW was significantly dependent on contact time, pH, dye concentration, adsorbent dose and pH. The optimum equilibrium conditions for removal of MB dye by PHW were; contact time of 2 hrs, at pH 8 and an adsorbent dose of 0.8 g. The adsorption data better fits Langmuir isotherm model well and the maximum adsorption capacity of the PHW was found to be 23.8 mg g-1. The results obtained in this study indicated that PHW will be an attractive candidate for removing cationic dyes from the dye wastewater.