Objective: Methicillin resistant Staphylococcus aureus (MASA) is one of the most important pathogens causing nosocomial infections. Genotyping epidemiologically related MRSA strains is useful in terms of determining the sources of infectious pathogens, potential carriers, ways of spread and enviromental factors and thus preventing and decreasing nosocomial infections. Pulsed field gel electrophoresis (PFGE) is accepted as the gold standard among the molecular methods used for investigation of genotypic relation. In our study, we aimed to genotype MRSA causing nosocomial infections by pulsed field gel electrophoresis. Material and Methods: In the study, genotypic relationship of 46 MRSA isolates that caused nosocomial infections in different clinics of our hospital between 2005 and 2007 were evaluated using PFGE method which genomic DNA cut by Sma1 enzyme. Isolates with PGFE band profiles resembling to each other 80% and above with Gel Compar II program were accepted as clonally related. Results: Forty two strains out of 46 were found to be closely related and took place in the same major "A" group while four strains were found to be unrelated. All of 12 MRSA strains isolated from reanimation clinic were found to take place in group "A" and 100% resemblance was found in eight of them. Conclusion: A single MRSA genotype was found to dominate and cause nosocomial infections in the three year period according to PFGE analysis results.