Abstract Background The prevalence and role of Chlamydia pneumoniae in chronic obstructive pulmonary disease (COPD) remain unclear. Methods Peripheral blood mononuclear cells were obtained from 100 outpatients with smoking-related, clinically stable COPD, and induced sputum was obtained in 62 patients. Results Patients had mean age (standard deviation) of 65.8 (10.7) years, mean forced expiratory volume in one second of 1.34 (0.61) L, and 61 (61.0%) were male. C. pneumoniae nucleic acids were detected by nested polymerase chain reaction in 27 (27.0%). Current smoking (odds ratio {OR} = 2.6, 95% confidence interval {CI}: 1.1, 6.6, P = 0.04), season (November to April) (OR = 3.6, 95% CI: 1.4, 9.2, P = 0.007), and chronic sputum production (OR = 6.4, 95% CI: 1.8, 23.2, P = 0.005) were associated with detection of C. pneumoniae DNA. Conclusions Prospective studies are needed to examine the role of C. pneumoniae nucleic acid detection in COPD disease symptoms and progression.