A case of self-limiting pneumonia due to Chlamydia pneumoniae is described. A 39-year-old male visited our hospital complaining of a persistent cough. No antibiotics were administered to this patient because of the absence of fever and a mild positive inflammatory response, but an infiltrate on a chest radiograph improved. Finally, a diagnosis of C. pneumoniae pneumonia was made by seroconversion of the C. pneumoniae-specific antibody and detection of the C. pneumoniae gene in bronchoalveolar lavage fluid. Self-limiting C. pneumoniae pneumonia is rarely encountered, although self-limiting upper respiratory tract infections due to C. pneumoniae are common. Thus, most self-limiting C. pneumoniae pneumonia may be missed when symptoms are minimal.