The objective of the study was to evaluate antimicrobial interactions between gentamicin (GEN) and zinc pyrithion (ZnP) against Streptococcus and Staphylococcus aureus strains. In vitro antimicrobial effect of GEN and ZnP was evaluated towards 7 strains of S. aureus, 2 strains of Str. agalactiae and one strain of Str. dysgalactiae by broth checkerboard method. Results show synergistic effect against three S. aureus strains (all were methicillin-sensitive strains) at one concentration of tested substances. In Str. agalactiae, both tested strains showed synergistic effect (at three and two concentrations, respectively). Combination of GEN and ZnP also showed synergism at three concentrations in Str. dysgalactiae.