Abstract: Objective To study the causes of secretory otitis media (SOM) in infants without adenoid hypertrophy. Methods Clinical data about 23 infants (36 ears) with SOM (adenoid hypertrophy was excluded) admitted to our department from 2000 to 2012 were retrospectively analyzed. Results Of the 23 infants, 6 (26.1%) were diagnosed with nasal sinusitis, 5 (21.7%) were found with a history of acute upper respiratory tract infection before SOM, 3 (13.0%) were diagnosed with bad mastoid pneumatization and congenital malformation of the external and middle ear, 1 (4.3%) with primary ciliary dyskinesia, 5 (21.7%) were found to have no clear abnormal structure and other lesions, and 5 (21.7%) were diagnosed with recurrent SOM. Conclusion The common causes of SOM in infants are adenoid hypertrophy, acute upper respiratory tract infection, nasal sinusitis and primary ciliary dyskinesia.