Algerian hospitals have experienced a dramatic increase in methicillin-resistant Staphylococcus aureus (MRSA) prevalence in recent years. To investigate this phenomenon, we have determined molecular characteristics of 61 methicillin-resistant or -susceptible strains isolated between 2003 and 2007 in Oran Hospital. Susceptible isolates were related to diverse genetic backgrounds, of which clone with sequence type (ST) 8 accounted for most of the samples. Resistance to methicillin was almost limited to two international spreading clones; the most frequent, ST80, contained isolates producing Panton-Valentine leukocidine, with SCCmec type IV. The increase of MRSA prevalence observed in Western Algeria, in outpatients as well as in hospitalized patients, is linked to dissemination of ST80 strains usually considered as community-acquired MRSA.