During a study of the monogeneans of three freshwater fishes (Ompok bimaculatus, Chanda nama, and Notopterus notopterus) from the River Ganga, a total of five parasites (Chandacleidus recurvatus, Notopterodiscoides notopterus, Spicocleidus namae, Thaparocleidus malabaricus, and Thaparocleidus octotylus) of the family Dactylogyridae were characterized molecularly (18S rRNA gene). Our study provides the first 18S molecular data for Chandacleidus recurvatus, Notopterodiscoides notopterus, Spicocleidus namae, Thaparocleidus malabaricus, and Thaparocleidus octotylus. The present study's phylogenetic analysis for the abovementioned species, developed here, revealed the importance of molecular approaches in the study of monogenean diversity. Although in Indian region, despite the high diversity of monogenean parasites from the freshwater fish hosts, little is known about their genetic diversity. Therefore, an integrative approach further will help to increase the exactitude of genetic diversity and phylogenetic relationships of this group of parasites.