A modified approach of hypophysectomy in the goldfish has been suggested. The main fea-ture of this method is that the pituitary gland is taken out from the opening made by cuttingthrough the anterior parl of the prootic instead of drilling through the parasphenoid bone onthe median oral roof. An incision about 3 mm. long was made through the opercular cavity onthe covering of the oral roof behind the eye. The opercular adductor muscle thus revealed wasexcised. By using a sharp fine scalpel the anterior portion of the prootic and the pterggoidangle of the parasphenoid were cut away. By pushing a little aside the external rectus muscleof the eye and the palatine branch of the Ⅵ eranial nerve, the pituitary gland was exposedand could be sucked away by a fine pipette of suitable size. The operation could be done within 5-7 minutes without doing any injury to the main ves-sels or nerves. Mortality after operation did not exceed 15% of fish operated at 25℃. The operation could be performed either by holding the fish in one hand and doing theoperation with the other or by fixing the fish on a specially designed operation board. Thisboard could also be used in operations other than hypophysectomy in fishes.