In an attempt to observe possible effects of ether and halothane anesthesia on the protein contents of the lung and liver of rabbits, the animal was subjected to the moderato anesthesia with either ether or halothane by non-rebreathing system for one hour, and the protein content of the lung and liver was measured by the method of Lowry et at. using Folin-phenol reagent. The comparison was made with the protein content from the normal rabbits, and the following results were obtained. l) The protein contents of the lung and liver of the normal rabbit were 45.0 ~ 11.5 mg/gm wet wt. and 100.4 ~ 15.1 mg/gm wet wt. respectively. 2) In the ether or halothane anesthesized group, the protein contents of the lung were 57.2 ~ 13.3 and 60.3 ~ 7.2 respectively. 3) In the anesthesia groups with ether and halothane, the protein contents of the liver were 103.4 ~ 10.0 and 90.1 ~ 13.0 respectively. 4) No significant difference in the protein contents of the lung and liver was observed after ether or halothane anesthesia comparing with the normal.