A worldwide taxonomic revision of the species belonging to the moss genus Chionoloma Dixon (Pottiaceae) is here presented. Our work is based on the morphological analysis of more than 2600 specimens deposited in different herbaria or collected during field trips. A total of 131 names were found and their nomenclatural types were examined, resulting in the lectotypification of 45 names. It is concluded that Chionoloma is composed of 22 species and one variety, seven of them are here newly combined (C. circinatum (Besch.) M. Alonso, M. J. Cano & J. A. Jiménez; C. cylindrotheca (Mitt.) M. Alonso, M. J. Cano & J. A. Jiménez; C. hyalinoblastum (Broth.) M. Alonso, M. J. Cano & J. A. Jiménez; C. melanostomum (Mitt.) M. Alonso, M. J. Cano & J. A. Jiménez; C. orthodontum (Müll. Hal.) M. Alonso, M. J. Cano & J. A. Jiménez; C. sarawakense (Dixon) M. Alonso, M. J. Cano & J. A. Jiménez; and C. stenocarpum (Thér.) M. Alonso, M. J. Cano & J. A. Jiménez). Moreover, 42 names are newly synonymized and a total of 74 new records for various countries are reported. Keys, descriptions, illustrations, photographs, and distribution data of each species are provided.