Adult patients who smoke are known to have airway complications during general anesthesia. The objective of this study was to explore the relationship between environmental tobacco smoke (ETS) exposure in the home and laryngospasm during general anesthesia in pediatric patients. A retrospective, cohort study was performed on pediatric ambulatory patients in the day surgery center and main operating room of a university hospital. We studied 310 consecutive pediatric patients (all ASA physical status I) who underwent an outpatient elective ear, nose, and throat or urologic surgical procedure in the spring and summer of 1994, and received inhalation induction by mask with halothane. Laryngospasm was identified from quality management and anesthetic records, and included only those patients whose records indicated that succinylcholine was given because of oxygen desaturation and inability to ventilate. Patients' families were questioned within 1 wk after surgery as to the number of smokers in each child's household. Of 96 children with ETS exposure, 9 (9.4%) developed laryngospasm. Of the 214 patients without domestic ETS exposure, 2 (0.9%) developed laryngospasm. The relative risk for developing laryngospasm was 10 times higher in the ETS-exposed patients compared with the non-ETS-exposed group (95% confidence interval = 2.2-45.6; P < 0.001). We conclude that ETS exposure is a strong risk factor for laryngospasm in infants and children during general anesthesia.