Abstract: Phase relations in the dry condensed Fe-Ir-S system were determined at 1100, 1000 and 800°C. Orientational runs were performed at 500°C. Between 1100 and 800°C, the system comprises five sulphides and an uninterrupted field of γ(Fe,Ir). Fe2−xS dissolves 5.8 at.% Ir at 1100°C, 3.4 at.% Ir at 1000°C and 1.0 at.% Ir at 800°C. The solubility of Fe in Ir2S3, IrS2 and IrS−3 increases with decreasing temperature, reaching 2.5 at.% in the latter two sulphides at 800°C. Thiospinel ‘FeIr2S4’ is non-stoichiometric, from Fe22.3Ir19.8S58.0 to Fe18.9Ir23.1S58.0, depending on as and aFe i.e. on a phase association. Thiospinel is absent at 800 and 500°C.