Parasitological studies were carried out on pulli (n = 20) collected on a breeding colony near the Włocławski Reservoir on the Vistula River (Central Poland). Larvae of the nematode Contracaecum rudolphii (mean intensity of infection 9.3) were detected in the stomachs of all chicks, with adult worms present in two chicks. Larvae of the nematode Porrocaecum ardeae (mean intensity 3.1), the tapeworm Paradilepis scolecina (58.5) and flukes of five genera: Tylodelphys, Posthodiplostomum, Apharyngostrigea, Paryphostomum and Echinochasmus (mean intensity in total 28.1) were found in the intestines of all chicks. The studies demonstrated that grey heron chicks are infected with parasites very early in life, which may adversely impact their health. The presence of adult C. rudolphii nematodes indicates a transfer of parasites from adult birds to chicks during feeding.