Landmark based morphometrics was used to investigate sexual dimorphism and interspecific differentiation in the mustelids Martes foina and M. martes, which are typical sexual size dimorphic species. Analyses were run on 192 specimens of M. foina and 36 specimens of M. martes from central and northern Italy, by recording 19 and 40 landmarks on the dorsal skull and on the palate, respectively. Results indicate that both size and shape are important components of skull dimorphism in males and females of the two species. The skull of the stone marten males is larger, has a narrower postorbital constriction and larger molars than in females. These differences and the partial least square analysis run on shape variable and stomach contents of one sample suggest that stone marten males are better adapted to catch and kill live prey, while females seem to prey upon easier-to-catch food. Shape features involved in sexual dimorphism are similar to those involved in interspecific variation, but the two species differ also in the relative size of their canines, carnassial and molar teeth, which are likely related to different ways of acquiring and processing preys.