The nematode, Camallanus xenentodoni Khan et Yaseen, 1969 recovered from the intestine of the fish, Xenentodon cancila (Ham.) from West Bengal, India was studied by light microscopy. Larval development of this nematode was also studied under laboratory conditions. Two cyclopoid copcpods, Mesocyclops crassus and M. leuckarti maintained at temperatures 28-31.5“C were infected with first-stage larvae from gravid females. In the haemocoelic cavity of the copepod the larvae moulted twice to attain third, infective stage and a phase of growth, development and morphometric changes occurred between the two moults. Detailed descriptions of the adult worms and the three larval stages are given. Data obtained from the morphological and metrical studies of the present adult worms are compared with those available on C. xenentodoni and another related species C. cancelai Gupta et Verma, 1978, which is considered as synonym of C. xenentodoni.