In present study, the synergistic separation of Cr(VI) has been investigated from synthetic acidic solution containing Cr(VI), Co(II) and Ni(II) by flat sheet supported liquid membrane (FSSLM) technique using triisooctylamine (TIOA) and tri-n-butyl phosphate (TBP) as carriers. The main goal of the study was based in the exploring of the synergistic effect of TBP on selective extraction of Cr(VI) in presence of Co(II) and Ni(II) ions. The various parameters related with membrane and aqueous solution properties were studied to identify the optimum extraction and stripping conditions of the Cr(VI) through FSSLM. In the optimum conditions, initial mass flux (J(0)) and separation factors (beta(Cr/Co) and beta(Cr/Ni)) were obtained as 1.49 x 10(-05) (kg/m(2.)s), 382.2 and 725.3 respectively from aqueous H2SO4 media through Celgard 2500 (Celgard Inc., USA) polymer support. As a result, the considerable synergistic influence on selective transport of Cr(VI) through FSSLM using TIOA and TBP as carriers has been identified.