The effect of a new analeptic, doxapram hydrochloride, on respiration has been studied in ten subjects anesthetized with thiopental or with nitrous oxide-oxygen-halothane. The results are as follows: 1) Respiratory stimulation was more pronounced in the group anesthetized with thiopental than that with nitrous oxide-oxygen-halothane. 2) The stimulatory effect lasted for four minutes. Subjects who received multiple doses of the drug, however, showed a cumulative effect. 3) Most cases showed moderate hypertensive effect and brief electrocardiographic change was observed in one of the ten.