The taxonomic status of four species of Avicularia Lamarck 1818 described from Uruguay: Avicularia anthracina (C.L. Koch 1842), Avicularia alticeps (Keyserling 1878), Avicularia parva (Keyserling 1878) and Avicularia tigrina (Pocock 1903) is discussed. The holotypes and/or original descriptions of these species were examined, and two taxonomic synonymies are needed, which are presented herein. Avicularia anthracina is transferred to Grammostola, resulting in Grammostola anthracina (C.L. Koch 1842) new combination and is considered a senior synonym of Grammostola mollicoma Ausserer 1875 new synonymy. Likewise, Avicularia parva is transferred to Catumiri Guadanucci 2004, where it is placed in the synonymy of Catumiri uruguayense Guadanucci 2004 new synonymy. Avicularia tigrina and Avicularia alticeps, originally described in the genera Ischnocolus Ausserer 1875 and Pterinopelma Pocock 1901, respectively, are herein considered nomina dubia since their types are presumed lost.