The work presented here focuses on the solution pretreatment and extraction stages of a solvent extraction system for rhodium from aqueous chloride solutions. The feed solution pretreatment stage involves a complexation reaction between the aqueous rhodium chloride complexes. [RhCl6-x(H2O)(x)]((3-x)-) and stannous chloride. Depending on the amount of stannous chloride used, at least two different Rh-Sn complexes are formed, either [Rh(SnCl3)(5)](4-) or [RhCl3(SnCl3)(3)](-3). Both of these respond well to extraction with Kelex 100, the extractant investigated in this work. The extraction stage was found to be quantitative for rhodium and it was also found to be very rapid, with contact times of less than 5 min sufficient for rhodium extraction. The extraction mechanism was determined to be ion-pair formation with the protonated Kelex 100 molecules at a stoichiometry such that the overall charge in the organic phase is neutral, i.e. three Kelex 100 molecules for [RhCl3(SnCl3)(3)](3-) and four for [Rh(SnCl3)(5)](4-).