Halfa or Cogongrass or speargrass (Imperata cylindrica (L.) Beauv.) is a perennial weed invading throughout the tropical and subtropical regions over the world. It causes many indirect environmental and economic problems and it's difficult to control. Therefore, two field experiments were conducted in Toshka Research Station, Desert Research Center, Egypt during 2018/2019 and 2019/2020 summer seasons (July and August) to evaluate the efficacy of fluazifop-p-butyl (inhibiting lipid synthesis) and glyphosate (disrupts the shikimic acid pathway through inhibition of the enzyme 5-enolpyruvylshikimate-3phosphate (EPSP) synthase) and some additives against this weed. In binary mixture trials, the recoded reduction in re-sprout of I. cylindrica rhizome at (2000 and 4000 ppm) of glyphosate and fluazifop-p-butyl alone and in combination with additives. Glyphosate plus gibberellic acid (GA3) reached (71.43and 85.71%), glyphosate and glycerin mixture (70.43 and 72.43%) while, glyphosate alone (28.57and 42.86%) respectively as compared with control. Under field condition, results showed that, the maximum reduction in dry weights of the I. cylindrica were (81.67%) at ½ rate of glyphosate plus GA 3, glyphosate plus IBA (70.70%) whereas, Fluazifop-butyl plus glycerin caused maximum reduction in dry weights (81.02 %) and Fluazifopbutyl at full rate plus glycerin (74.58 %) in the first season and second season, respectively. Further research on the effects of the best herbicides selectivity is needs with combination of additives, mechanical, and agricultural methods on I. cylindrica control under the field conditions.