The family Callitrichidae comprises the small clawed neotropical primates commonly known as marmosets and Tamarins. Although several reports of parasitological surveys of New World primates may be found scattered in the literature of recent years, little is know about the natural parasitism of marmosets in Brazil. Callithrix geoffroyi, C. jacchus (known as "common marmosets") and C. penicillata are being maintained and successfully reared in captivity and their natural infection by parasites are studied. Among them, some specimens of Callicebus personatus nigrifons, which were maintained in captivity to be reintroduced in another area near their natural habitat, in a parasitological survey it was verified that primates were passing eggs of Primasubulura jacchi and Cestodes belonging Anaplocephalidae and Hymenolepididae families, in their faeces. At the present, is the first official register of P. jacchi and Mathevotaenia megastoma for C. p. nigrifons in Brazil.