Crocidura tadae was first reported as a new species from Orchid Island by Tokuda & Kano (1936). However, both C. tadae and C. kurodai from Taiwan were considered as subspecies of C. horsfieldii by subsequent researchers. In the present study, the karyotypic and morphological differences among the potential C. tadae specimens from Taiwan main island and two offshore islands (Orchid Island and Green Island) were examined. The results revealed that there is no significant difference in the karyotypes of these shrews but that their karyotype is different from that of other Crocidura species. Therefore, the Tadae's shrew C. tadae Tokuda & Kano, 1936 should be a valid species. Furthermore, morphological variation in 25 external and cranial characters of 106 specimens were analysed using univariate statistics, and eight selected characters were used for multivariate analyses. Univariate statistical comparisons of the three insular samples revealed that shrews of the Green Island population were the largest in most measurements of characters and shrews of the Orchid Island population were the smallest. Multivariate analysis differentiated the Taiwan samples from the other two insular samples. Therefore, three subspecies of C. tadae are recognized: C. t. tadae (Orchid Island); C. t. kurodai (Taiwan) and C. t. lutaoensis subsp. nov (Green Island).