This work is devoted to the study of the complexing in the system cobalt (II) – dithiooxamide – alkylbenzene sulfonates and platinum (IV) – dithiooxamide – alkylbenzene sulfonates using spectrophotometry. The wavelengths of maximum light absorption of the complexes, which were 435 nm for dithiooxamide complex of cobalt (II) and 370 nm and 470 nm for dithiooxamide complex of platinum (IV), were determined at a 1: 1 ratio of main components. The effect of the acidity of the medium on the complexation reaction was studied; the range of pH values at which the most complete binding of metal ions occurs is revealed. The kinetics of the formation of dithiooxamide complex of cobalt (II) at pH = 7.5, dithiooxamide complex of platinum (IV) at pH = 3 was studied. It has been established that in the system under study, dithiooxamide complex of cobalt (II) is stable for 25 hours, and dithiooxamide complex of platinum (IV) for 14–24 days. Using the methods of isomolar series and molar relations, graphic dependencies were obtained; the ratio of the components of dithiooxamide : cobalt (II) and dithiooxamide : platinum (IV) in the complex was determined by their mathematical processing in the program OriginLab 8. In addition, on the basis of the data obtained, the values of the stability constant of dithiooxamide complex of cobalt (II) were calculated.