The platinum-catalyzed self-cross-linking of polymethylhydrosiloxane at RT in air was performed for the first time and proved by ¹H, ¹³C, and ²⁹Si SSNMR and swelling measurements. Quantum chemical modeling of possible structures was investigated. Platinum (0) and (ii) complexes were used as catalysts between the Si-H groups of polymethylhydrosiloxane. Karstedt's catalyst leads to Si-O-Si and Si-Si bond formation, but cis-[PtCl ₂(BnCN) ₂] generates predominantly Si-O-Si cross-links. cis-[PtCl ₂(BnCN) ₂] allows creating high-quality silicone rubbers without visible mechanical defects. This cross-linking approach can be used to obtain new Si-H-containing silicone materials.