The genus Minibiotus is redefined and the type species, Minibiotus intermedius (Plate, 1889) is redescribed. Eleven new species of Minibiotus are diagnosed and described, and three are transferred from the genus Macrobiotus using a range of qualitative and quantitative characters of adults and eggs. Keys are provided to the adults of the 22 reported species in the genus and to the eggs of the 20 species for which eggs have been described. Characters useful in discriminating species with very similar morphology are noted. The difficulties inherent in taxonomic studies of small animals such as many of those in the genus Minibiotus are discussed as are the problems of recognition of species in groups where both the adult form and sometimes also the egg are very similar. The examination and description of the eggs is important in tardigrade taxonomy.