We examined Japanese case reports to evaluate the efficacy of steroid treatment for community-acquired Legionella pneumonia during the acute phase. Eighty-one patients with community-acquired Legionella pneumonia were selected as the subjects of this study, from among the cases retrieved using Igaku Chuo Zasshi (Ichushi) search engine between January 2000 and December 2016. Data regarding the severity of pneumonia and length of hospitalization were obtained for all subjects. The proportion receiving steroid treatment did not differ between the subjects who died and those who survived. However, steroids were more frequently used in subjects with a longer length of hospitalization (>29 days) than in those with a shorter stay in hospital. Multivariate logistic regression showed that the use of steroids (p=0.023) and high C-reactive protein levels (p=0.0086) were significantly correlated with hospitalization for more than 29 days. Therefore, the use of steroids during the acute phase was not effective for treating community-acquired Legionella pneumonia.