[en] The procedure for the standardization of "5"9Fe using a 4π(PC)β–γ software coincidence system is described. The standardization was performed with an experimental setup consisting of a thin window gas-flow proportional counter (PC) in 4π geometry coupled to a NaI(Tl) scintillator and to a HPGe detector. The data acquisition was carried out by means of a Software Coincidence System (SCS). The beta efficiency was changed by using Collodion films and aluminum foils as external absorbers. - Highlights: • "5"9Fe standardised by 4π(PC)β–γ software coincidence system. • Thin windowed proportional counter employed along with both HPGe and NaI(Tl) detectors. • Good agreement between 4π(PC)-HPGe and 4π(PC)-NaI(Tl) results.