BACKGROUND: This study aimed (a) to provide information on methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization ratio in residents of nursing homes; (b) to determine the effect of hand-washing education given to nursing home residents and employees on nasal carriage of Staphylococcus aureus (NCSA) and (c) to obtain probable risk factors for MRSA colonization of residents in two nursing homes. METHODS: Seventy-nine volunteers (24 females and 55 males) from Bolu nursing homes were included in the study. Nasal samples were taken with sterile swabs from the anterior nares. Staphylococcus aureus strains were identified using classical methods and genotyping of methicillin resistant strains was done using Arbitrary Primed PCR (AP-PCR). Antibiotic susceptibilities were determined by disk diffusion methods according to NCCLS standards. After first nasal samples were taken, all employees and residents of nursing homes were educated about the methods of hand hygiene over two days. RESULTS: With hand-washing education, the decrease of NCSA rate (initially 43%; after education, 21%) was significant (p < 0.05) while decrease of MRSA carriage (initially 5%, after education 1%) was not (p > 0.05). MRSA carriage was significantly correlated with presence of skin lesions, prior hospitalization within the last six months, and antibiotics usage within the last six months. AP PCR results suggested that residents' carriage of MRSA was the result of the same source. CONCLUSION: MSSA and MRSA colonization rates were found to be 38% and 5% in nursing homes, respectively. These ratios can decrease with simple precautions like hand-washing after a short education period