In this research work, the possibility of using hydrocyclones to separate Saccharomyces serevisiae 5209 from a prepared media was studied. The cell separation can be very useful in order to improve the quality of alcohol produced, reduce energy consumption and also reduce the cost of effluent treatments with the hydrocyclone advantage of consuming less energy. A hydrocyclone with 15 mm internal diameter was used for cell separations. A better separation efficiency of 3.84 (gram cell dry weight in: under flow/over flow) was obtained at volumetric flow rate of about 112 cm(3)/s. (C) 2007 Elsevier B.V. All rights reserved.