It is thought that surface melting and puffing of freeze-dried amorphous materials are related to the difference between the surface temperature (T sur ) and freeze-concentrated glass transition temperature (T g ') of the materials. Although T g ' is a material-specific parameter, T sur is affected by the type and amount of solute and freeze-drying conditions. Therefore, it will be practically useful for preventing surface melting and puffing if T sur can be calculated using only the minimum necessary parameters. This study aimed to establish a predictive model for the surface melting and puffing of freeze-dried amorphous materials according to the calculated T sur . First, a T sur -predictive model was proposed under the thermodynamic equilibrium assumptions. Second, solutions with various solute mass fractions of sucrose, maltodextrin, and sucrose-maltodextrin mixture were prepared, and three material-specific parameters (T g ', unfrozen water content, and true density) were experimentally determined. According to the proposed model with the parameters, the T sur of the samples was calculated at chamber pressures of 13, 38, and 103 Pa. The samples were freeze-dried at the chamber pressures, and their appearance was observed. As expected, surface melting and puffing occurred at calculated T sur > T g ' with some exceptions. The water activity (a w ) of the freeze-dried samples increased as the T sur - T g ' increased. This will have resulted from surface melting and puffing, which created a covering film, thereby preventing subsequent dehydration. The observations suggest that the proposed model is also useful for predetermining the drying efficiency and storage stability of freeze-dried amorphous materials.