In this paper an attempt has been made to preconcentrate the sulphide minerals from complex sulphide ore by selective flocculation using a modified flocculant such as cellulose xanthate. The experiments carried out indicated that the metal grades were enhanced from 2 to 3.3% for lead and from 6 to 10.57% for zinc. The effectiveness of the process was assessed by a selectivity index which indicated that the process is effective and resulted in an index value of 0.3 for lead and 0.35 for zinc.