The infestation by a relatively less known monogenean, Dactylogyrus cornu Linstow, 1878, was investigated on vimba, Vimba vimba tenella Nordmann, 1840 in a small stream pouring into the Black Sea in Sinop, Turkey. A total of 122 fish specimens were examined in June 2000. The overall infestation prevalence and mean intensity levels were 100% and 147.7 +/- 7.9 parasites per infested fish, respectively. D. cornu was recorded only on the gills of host fish and possible site specificity to the filaments of the second gill arches of the left and right gill arch sets was recorded. The parasite was also found to be settled more on female and larger host fish.