To investigate whether the type of anesthetic agent administered affects the antitussive effect of remifentanil.Prospective randomized study.Operating room of a university hospital.78 ASA physical status 1 and 2 women, aged 20 to 65 years, who were scheduled to undergo a thyroidectomy.Patients were randomly assigned to three groups to receive anesthesia with propofol (Group P), sevoflurane (Group S), or desflurane (Group D). The main anesthetics were titrated to maintain a target Bispectral Index for hypnosis of 40 to 60. Remifentanil was administered via effect-site target-controlled infusion (TCI). To determine the effective remifentanil effect-site concentration (Ce) to suppress coughing in each group, the up-and-down sequential allocation design was used.The half maximal effective concentration (EC50) values of remifentanil for preventing coughing in the groups were estimated using isotonic regression and compared among the groups.The EC50 of remifentanil for cough suppression in Group P [1.60 ng/mL (98.3% CI, 0.92-1.75 ng/mL)] was statistically lower than in Group D [1.96 ng/mL (98.3% CI, 1.81-2.50 ng/mL)]. The EC50 in Group S was 1.75 ng/mL (98.3% CI, 1.39-2.13 ng/mL), which was higher than in Group P and lower than in Group D, but did not differ significantly from either group.Remifentanil administration for cough suppression during emergence should be customized to the anesthetic agent.