AbstractRattus norvegicushas attracted much attention because of its role as a reservoir of zoonotic pathogens. This work aimed to identify the intestinal helminth species inR. norvegicusand to analyse the effects of temperature, rainfall, host age and sex on the helminth community structure. Moreover, this study investigated the possible associations among helminth species in an urban population ofR. norvegicusin São Gonçalo, Rio de Janeiro, sampled during the rainy and dry seasons over a span of 2 years. A total of 112 rats were infected by six species of helminths. The nematodeNippostrongylus brasiliensiswas the most prevalent and abundant species, with high mean intensity in both seasons, followed byStrongyloides venezuelensis,Heterakis spumosa,Raillietinasp.,Hymenolepis nanaandMoniliformis moniliformis.Co-occurrence was found betweenN. brasiliensisandS. venezuelensisand betweenN. brasiliensisandH. spumosa.The occurrence ofS. venezuelensiswas related to rainfall. The understanding of the helminth community structure in this synanthropic rat provides basic information on parasites of public health importance, as two helminth species (H. nanaandM. moniliformis) recovered from rats in the urban area studied can infect humans.