The modified quasichemical model for short-range ordering is described for liquid metal-sulfur solutions. Available thermodynamic data for molten Fe-S, Ni-S, Cu-S, and Co-S solutions are collected, critically evaluated, and optimized by means of the model. Very good descriptions of the thermodynamic properties are obtained with few parameters. Using only these binary parameters, the model predicts the thermodynamic properties of Fe-Ni-S, Fe-Cu-S, Ni-Cu-S, and Fe-Ni-Cu-S mattes over a wide range of composition and temperature within experimental error limits.