The transfer of Nb(V) and Ta(V) ions in a chloride medium across a supported liquid membrane containing tributyl phosphate as carrier has been investigated. Conditions for feed solutions were analyzed by means of liquid-liquid extraction experiments. The transport experiments were carried out with a permeation cell with a continuous flow system and constant agitation. The hydrochloric acid concentration in the feed solution has a marked effect on Nb(V) transport. With increasing hydrochloric acid concentration the transport of Niobium (V) increased and a maximum flux between 6 and 9 M of HCl was obtained. The Ta(V) was transported in small amounts at HCl concentration up 6 M, so that a selective separation of Nb(V) from Ta(V) could thus be performed. (C) 2000 Elsevier Science B.V. All rights reserved.