To clarify whether the environment of a nursing home affects the clinical features of patients with pneumonia, we compared the characteristics of 103 patients (nursing home group) who suffered from pneumonia at a nursing home with 153 elderly patients with the same background (community group) who lived in their own home. Although there were no significant differences in CRP, WBC, and body temperature at admission and duration of hospitalization, the degree of independency of the nursing home group was significantly lower than the community group. As the degree of independency became worse, the length of hospitalization extended and mortality increased. Bacteriological findings of sputum culture showed that methicillin-resistant Staphylococcus aureus (MRSA) was cultured in 20 cases (19%) of the nursing home group and 18 cases (13%) of the community group. In isolated analysis of total care cases, MRSA positive rates were similar in the nursing home group (17/58; 29%) and the community group (8/30; 27%). Only 1 case with penicillin-susceptible Streptococcus pneumoniae (PSSP) was found in the nursing home group, however 7 species of PSSP were cultured in the community group, including 5 self-help cases. Pseudomonas aeruginosa was cultured in 8 patients of each group, and most of them were total care cases. We concluded that the difference in frequency and species of bacteria depended on the condition of patients, rather than the environment, and differences in conditions might lead to differences in clinical features.