We present results of correlative measurements of platinum–hydrogen (Pt–H) complexes in silicon using infrared absorption (IR) and ESR measurements. Relative concentrations of the complexes in the samples were varied employing various gas pressures during hydrogen doping procedure. The ESR and IR results for the PtH2 and PtH3 complexes showed good correlation in various samples, supporting the existing identification of the IR peaks. The ESR and IR signals assigned to PtH pair, however, behaved differently. Our results suggest that the IR peak assigned previously to PtH pairs only, contains several unresolved components corresponding to PtmH (m⩾1) defects.