The mesostigmatid genus Andreacarus Radford, 1953 (Acari: Laelapidae), species of which are obligatory parasites of small mammals, is revised. Andreacarus includes 11 species, four species previously recognized and seven new species described from Madagascar hosts: A. brachyuromys sp. n. from Brachyuromys betsileoensis Bartlett, A. eliurus sp. n. from Eliurus species, A. gymnuromys sp. n. from Gymnuromys roberti Major, A. voalavo sp. n. from Voalavo gymnocaudus Carleton & Goodman, A. nesomys sp. n. from Nesomys rufus Peters—all from nesomyid rodents; A. tenrec sp. n. from Tenrec ecaudatus Schreber (Afrosoricida: Tenrecidae); and A. galidia from Galidia elegans I. Geoffroy Saint-Hilaire (Carnivora: Viverridae). An amended generic diagnosis and key to females are also given. Six species described in Andreacarus from Australian and New Guinean hosts are removed and transferred to the new genus, Juxtalaelaps.