Healthcare-associated pneumonia (HCAP) is a new concept of pneumonia, which was proposed in the ATS/IDSA guidelines. The guidelines explain that HCAP patients should be treated with broad-spectrum antimicrobial drugs directed at multidrug-resistant pathogens. However, in Japan, there are many elderly people who received in-home care service. These patients seemed to be consistent with the concept of HCAP, but they did not meet the definition of HCAP. Therefore, the Japanese Respiratory Society modified the definition of HCAP according to the medical environmental in Japan. We retrospectively observed HCAP patients and nursing home and healthcare-associated pneumonia (NHCAP) patients who were hospitalized during 24 months at the Japanese Red Cross Nagasaki Genbaku Hospital (Nagasaki, Japan). Patient background, disease severity, identified pathogens, initial antibiotic regimens, and outcomes were compared. A total of 108 patients (77 HCAP and 31 NHCAP except HCAP patients) were evaluated. Of NHCAP except HCAP patients, 27 (87.1 %) were above 3 in the ECOG PS score. There were almost no significant differences between the two groups in characteristics, pneumonia severity, identified bacteria, initial antibiotic regimens, and response rate of initial antibiotic therapy. Although the in-hospital mortality of HCAP patients and NHCAP except HCAP patients was 9.1 % and 19.4 %, respectively, this difference did not reach statistical significance (P > 0.05). Our study suggested that, in the criteria of HCAP, some Japanese patients, who were consistent with the concept of HCAP, were classified as community-acquired pneumonia (CAP). Therefore, there is a need to change the definition of HCAP according to the medical environment in Japan.