Dactylogyrus is a holarctic genus of monogene flatworms that infects the gills of cyprinid fishes. Dactylogyrus species are usually highly host specific, and little is known about their life history in North America. The purpose of this study was twofold: to determine 1) whether Dactylogyrus exhibits seasonality in its life cycle, and 2) if there is any potential effect upon reproductive effort of the host as a result of Dactylogyrus infection. Over a 12-month period, 967 Dactylogyrus were found on the gills of 383 Notropis telescopus (Telescope Shiner), a cyprinid fish collected in the upper Paint Rock River system in northeastern Alabama. A significant positive relationship was found between prevalence of infection and host somatic weight and gonadosomatic index (GSI). The assumptions that parasite presence is evenly distributed among individual host fish and within each month were rejected by chi square tests, with the months of March through July as a peak for the extent of Dactylogyrus infection. These months are the time of gonadal development and reproduction in Telescope Shiners.