BackgroundTwo studies have observed that growth media containing gentamicin can inhibit the growth of the yeast organism Malassezia pachydermatis. The minimum inhibitory concentration (MIC) of this bactericidal antibiotic for this organism has not been previously determined.ObjectiveTo evaluate the susceptibility of M. pachydermatis isolates to gentamicin.MethodsThe MIC of gentamicin was determined using a modified version of the M27‐A3 microdilution method following the guidelines of the Clinical and Laboratory Standards Institute. A modified Christensen's urea broth was used to enhance the growth of the M. pachydermatis isolates. Visual and spectrophotometric end‐point readings were performed to detect the presence or absence of yeast growth.ResultsThe MIC50 and MIC90 of gentamicin were 8.12 μg/mL and 32.5 μg/mL, respectively; M. pachydermatis strains were classified as susceptible (S), intermediate (I) and resistant (R). The susceptibility of these isolates to gentamicin in vitro, by visual and spectrophotometric end‐point reading, was: S, 54–56%; I, 40–41%; and R, 3–6%.ConclusionProspective MICs for M. pachydermatis have been established for gentamicin.