In this study, the extraction of Bi(III) from synthetic solutions of 2 M H 2 SO 4 /0.5 M HCl by supported liquid membranes (SLM) using tri-noctylphosphine oxide (Cyanex 921) as extractant is reported. First, the nature of the Bi(III)/Cyanex 921 solvates extracted to organic phase (in a solvent extraction system) was determined by the slope method. It was found that Bi(III) reacts with 2 molecules of Cyanex 921 to form the solvate BiCl 3 β’2Cyanex 921. In the recovery of Bi(III) by the SLM system, parameters that influence extraction efficiency were evaluated, including: support, feed solution and stripping solution nature, and extractant concentration in the organic phase which impregnates the support. Results indicate that Cyanex 921 dissolved in kerosene is not able to extract Bi(III) from H 2 SO 4 media. Moreover, transfer of H 2 SO 4 was observed. HCl addition to the feed solution up to a maximum concentration of 0.5 M increases Bi(III) extraction. Further increase in HCl concentration causes a decrease in Bi(III) transfer. Likewise, the concentration of Cyanex 921 in the SLM organic phase which produced the maximum Bi(III) extraction was found to be 0.3 M. The performance of H 2 O and 0.2 M H 2 SO 4 as stripping solutions was evaluated, and it was found that only H 2 SO 4 enabled Bi(III) transfer.