Objective To investigate the recent studies about the relationship between Chlamydia pneumoniae and abdominal aortic aneurysm. Methods The current literatures about the relationship between Chlamydia pneumoniae and abdominal aortic aneurysm were reviewed. Results Chlamydia pneumoniae is one of the most important factors for the formation of abdominal aortic aneurysm since Chlamydia pneumoniae can cause abdominal aortic aneurysm through the metabolism of matrix metalloproteinases, the apoptosis of smooth muscle cells in the vessels and the chronic infection of the wall of the aneurysm. Conclusion There maybe a distinguishingly close relationship between Chlamydia pneumoniae and abdominal aortic aneurysm, and Chlamydia pneumoiae may take an important role in the development and progress of the abdominal aortic aneurysm.