Staphylococcus aureus causes a range of illnesses from minor skin infections to life-threatening pneumonia, meningitis, and sepsis. Furthermore, many S. aureus strains, particularly those isolated from hospitals, carry genes for resistance to antibiotics. Annual medical expenses caused by S. aureus infections in the EU and US were estimated to be more than €380 million [1] and $2 billion, respectively. In 2017, the World Health Organization listed S. aureus among the twelve most threatening antibiotic-resistant pathogens for which new treatments are urgently needed. Phage therapy is an alternative to antibiotics for treatment of staphylococcal infections. Phage phi812K1/420 infects 95% of Methicilin-sensitive S. aureus strains and at least 75 % of Methiciline-resistant strains [2]. However, before it can be applied as therapeutics, it is important to know the detailed structure of the virus particle. Here we show the current state of structural research of phage phi812K1/420 proteins BmpA, B, and C. BmpA and BmpB are being optimized for expression. BmpC was succesfully crystallyzed and diffraction data were recently collected. All proteins are part of the base plate, which is responsible for the attachment of the phage to host cell. The structure determination of the base plate proteins can reveal important informations about the infection process. We anticipate our study to be another step in introduction of staphylococcal phages as therapeutic agents.