A new nematode belonging to the Cystidicolidae is described. Pseudascarophis genypteri n. sp. was found in the intestine of the red ling Genypterus chilensis, sampled off Talcahuano, Chile. It is distinguished from Ascarophis species mainly by the absence of cephalic papillae and of submedial and medial labia. The other species in the genus, Pseudascarophis kyphosi Ko, Margolis, and Machida, 1985, found in Kyphosus cinerascens, and P. tropica (Solov'eva, 1996), found in Parupeneus chrysopleuron, differed principally from P. genypteri in the form of pseudolabia, number of pre- and postanal papillae, and length of spicules.