Sedum piaxtlaense is described as a new species based on a collection in the Rio Piaxtla Canyon, growing in tropical deciduous forest in the Sierra Madre Occidental near the border of the Mexican states of Durango and Sinaloa. This new species belongs into the section Sedastrum (Rose) A. Berger whose distinctive morphological characteristics are basal rosettes, generally pubescent leaves, concave carpel base, usually paniculate inflorescences, and white corollas, the only exceptions being Sedum glabrum and S. jarocho which do not show any pubescence in their floral structures. S. piaxtlaense is apparently closely related to S. hintonii and S. mocinianum from which it differs in the laxer rosettes, concave leaves of larger diameter, as well as a shorter inflorescence with up to eight flowers per cincinnus and large pedicels, and its distribution in another biogeographical province.