In this paper, we propose a novel promising route for the direct synthesis of nanoscale iridium and tin oxide nanolayers by a successive ionic layer deposition method (SILD). The precursors for the synthesis included an aqueous solution of SnF₂ with an equilibrium pH value and the colloidal solution of IrO_x∙nH₂O nanoparticles and Na₂[Ir(OH)₆] mixture with pH = 10.5, obtained by the alkaline hydrolysis of the H₂IrCl₆ solution. The synthesized nanoscale oxide exhibited electrocatalytic properties in the oxygen evolution reaction (OER) upon water splitting in the acidic medium. A series of samples were obtained, synthesized as a result of 10, 30, and 50 SILD processing cycles. It was found that the films obtained as a result of 30 SILD cycles and heated in argon at a temperature of 300 °C had the best electrocatalytic properties in the reaction of oxygen evolution in the HClO4 solution. For these films, the overpotential value at a current density of 10 mA/cm² was 288 mV and the Tafel coefficient value totaled 56 mV/dec. Investigations by SEM, TEM, EDX, XRD, XPS and FTIR spectroscopy revealed that the samples were built of Ir_0.7SnO_x∙nH₂O amorphous nanoparticles with a size of 10–20 nm. For this kind of electrode, estimation of the specific mass of iridium showed that its amount is about 0.02 mg/cm². It is suggested that the new synthetic method may serve as the basis for creating a wide range of coatings for electrodes in electrochemical devices, including electrochemical sensors, electrical stimulators, electrochromic devices, etc.