The presence of Cucullanid nematodes was investigated in 10 individuals of Mugil bananensis, 115 Mugil cephalus, 109 Mugil curema, 89 Liza dumerili, 37 Liza falcipinnis, and 40 Liza grandisquamis, all collected from the Saloum estuary in Senegal, West Africa. Cucullanids were found only in intestines removed from M. curema and were identified using light microscopy. The results showed that 13 individuals of Mugil curema were found to be parasitized by 22 adult nematodes of a species new to science, Cucullanus djilorensis n. sp. (prevalence 11.9%, intensity 1.7). This species differs from all other species of the genus Cucullanus by a number of features including the form of the esophagus, the number and distribution of caudal papillae, the position of the excretory pore, and the length of the spicules. Cucullanus djilorensis n. sp. is the first species of the genus described from an estuarine fish in West Africa.