A telephone interview with the parents of 84 children who underwent tonsillectomy was conducted within 24 hours after discharge from an ambulatory surgery center. Parents were asked to rate the intensity of their child's pain and data were collected on the type, dose, and amount of analgesics administered, and the types of side effects the children experienced. The mean age of the children was 7 years (SD = 2.31), with an equal number of boys and girls. Overall mean pain intensity was 1.42 (SD = 0.71) and the worst pain intensity ranged from 0 to 3 (Mean = 1.93; SD = 0.83). Acetaminophen with codeine was the most common analgesic prescribed and administered. Children received an average of 3 doses in the first 24 hours after surgery. Seventy-seven percent of the parents stated that pain relief from the analgesic was adequate. Of the 23% who did not feel that pain control was adequate, only 7% contacted a physician. The majority of the children experienced restless sleep (62%), behavior changes (75%), and difficulty taking oral fluids because of complaints of pain (56%). Twenty-six percent of the children had one or more episodes of emesis. Our data suggest that children experience a significant amount of pain in the first 24 hours after tonsillectomy and that parents administer analgesics less frequently than the drugs are prescribed. In addition, children experience significant deleterious effects (i.e., poor oral fluid intake, sleep disturbance, behavioral changes, and emesis) associated with the undertreatment of pain, the analgesic administered, or the surgery itself.