Di-n-pentyl sulfoxide (DPSO) was employed for the solvent extraction separation of some transition metals from hydrochloric acid medium. It was found that chromium(VI) gets extracted at low acid concentrations (3 to 4.5M), and iron(III) and cobalt(II) only above 5MHCl. Nickel was not extracted at any of the test conditions. These transition metals were separated from one another by suitable choice of the extraction conditions.