© 2015 Informa UK Limited, trading as Taylor & Francis Group.Context: There is a great necessity to find and use accomplished terminal sterilization technique for industrial manufacturing, research and development studies. Gamma (γ)-sterilization has been commonly employed for wide range of products as indicated by the pharmacopoeias. However, carefully examination should be performed prior to administration since γ-radiation can cause changes in drug and polymer excipients. No information is available in literature about γ-sterilization effects on vancomycin HCl-loaded poly (ɛ-caprolactone) (PCL) microspheres. Objective: Formulations were developed using a different preparation approach for the treatment of medical device-related osteomyelitis, and γ-sterilization effects on the physicochemical characterization of the formulations were examined. Methods: Water-in-oil-in-water (w/o/w) emulsion technique using polyvinyl alcohol (PVA) in inner and outer phase was applied to prepare formulations. Physicochemical properties of the formulations were investigated before and after γ-sterilization and the antibacterial activity against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) were measured. Results: The particle size of the nonsterilized formulations were between 58 and 134 μm. 60% or 20% of vancomycin HCl were released from 42.500 Mn or 70.000–90.000 Mn PCL microspheres, respectively, in 24 h. No difference was observed in the particle size, drug-loading efficiency, morphology, in vitro release and antimicrobial activity of the formulations after γ-sterilization (p > 0.05).