Staphylococcus epidermidis is considered an important nosocomial pathogen, being very tolerant to the host immune system and antibiotherapy, particularly when in biofilms. Due to its high resistance, alternative antimicrobial strategies are under development. The use of bacteriophages is seen as an important strategy to combat pathogenic organisms. In this study, a S. epidermidis myovirus, SEP1, was isolated and characterized. The genome of this phage was sequenced and shown to be peripherally related to the Twortlikevirus genus. However when compared to other phages of this genus, it showed DNA sequence identities no greater than 58.2%. As opposed to other polyvalent viruses of the Twortlikevirus genus, SEP1 is highly specific to S. epidermidis strains. The good infectivity showed by this phage as well as its high lytic spectrum suggests that it might be a good candidate for therapeutic studies. ; L. D. R. M. and S. S. acknowledge Fundac??a??o para a Cie??ncia e a Tecnologia grants SFRH/BD/66166/2009 and SFRH/BPD/48803/2008, respectively. We thank Gabriele Bierbaum (Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, Bonn, Germany) for providing some strains.