STEMdiff™ Neural Progenitor Freezing Medium is a serum-free medium for cryopreservation of neural progenitor cells (NPCs) derived from human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells. This freezing medium is optimized for the cryopreservation of NPCs generated using STEMdiff™ Neural Induction Medium (Catalog #05835) and cultured in STEMdiff™ Neural Progenitor Medium (Catalog #05833). NPCs can be frozen at any point post neural induction, with reproducibly high recovery rates. Post thawing, NPCs display healthy morphology, express NPC markers, and retain the potential to expand and differentiate into neurons.