Abstract: A method called the initial zero recycle method has been proposed for the calculation of the material balance of processes with recycle streams. The method is a modification of the classical Cut And Try Method. The proposed method has been illustrated with the calculation of the material balance of the industrial process for the synthesis of cumene (isopropylbenzene) from benzene and propylene at 623 K (350�C) and 30 atm. The results show that the solution of the material balance of the process was achieved at the end of four iteration cycles.