OBJECTIVE To determine the effect of passive smoking on otitis media with effusion (OME) and recurrent otitis media (ROM). DESIGN A case-control study of children who received ventilation tubes and who were followed up for 1 year to determine the risk of developing postoperative otorrhea and early extrusion in relation to exposure to passive cigarette smoke. SETTING Otorhinolaryngology Clinic of Istanbul School of Medicine, Istanbul, Turkey. PATIENTS A total of 166 children 3 to 7 years old who required tympanostomy tubes because of OME and ROM (case group) compared with an age-matched control group of 166 children. The control group consisted of children who did not meet and never had met criteria for insertion of tympanostomy tubes. MAIN OUTCOME MEASURES Statistical analysis of factors associated with a higher prevalence of OME or ROM, postoperative otorrhea, and early tube extrusion. RESULTS Passive smoking was a significant risk factor for OME and ROM. The case group was exposed to a mean of 19.6 cigarettes per day vs 14.4 cigarettes per day for the control group (P<.004). Only maternal smoking was a significant factor (P<.001); no association was found with paternal smoking. Prospective follow-up of the case group showed no significant difference in the clinical course of OME and ROM between maternally exposed and non-maternally exposed children. CONCLUSIONS Passive smoking increases the risk of OME and ROM in children between 3 and 7 years old. The avoidance of daily exposure to domestic tobacco smoke could have a public health impact.