From the zoological standpoint, Alaska is poorly known, and it is particularly evident that the parasitic fauna of the region remains virtually unexplored. In connection with studies on animal-borne diseases conducted under the direction of Dr. Robert Rausch, by the parasitology branch of the Arctic Health Research Center, a considerable volume of helminthic material is obtained. It is the intention of the staff concerned with these studies to release the resulting information as a series of publications of which the present paper is the first. Sixteen specimens of Sabine's gull (Xema sabini) were collected during the latter part of July and early August of 1949. A single specimen was taken at Point Barrow and the other fifteen at the mouth of the Alaktak River near Admiralty Bay, east of Point Barrow. Of the total number, nine were found parasitized by cestodes representing two species herein described as new.