Abstract <p>The results of studies on platinum extraction from a spent refining mother liquor are presented. The problem of the studies is determined by a question whether it is possible extracting platinum with a concentration of about 20–50 mg/dm³ from a low-concentration refining mother liquor, wherein platinum is present as such a Pt(IV) aquachloro complex as [Рt(H₂O)₂Сl₄]^2–. It has been found that the best level of platinum extraction (99.9%) into the cake can be achieved using a solution of rongalite and thiourea under the conditions of pH &lt; 2.2 and <i>T</i> = 22°С.</p>