Research into multiple sclerosis (MS) has shown that cells purportedly important to myelin repair within the CNS, namely neural stem cells (NSC) and oligodendrocyte progenitor cells (OPC), are recruited to active lesion sites during the course of the disease. However, over time these cells appear to become depleted or functionally blocked in and around lesions, accompanied by a failure of repair mechanisms. We have previously demonstrated elevated CXCL8 in patients with MS, and hypothesized that this chemokine may play a role in the pathology of this disease. Using NSC and OPC derived in vitro from human embryonic stem cells (hESC) we demonstrate here that CXCL8 has a dual role on stem cell biology in vitro. CXCL8 caused CXCR1-mediated death of NSC, but not OPC, whilst also acting as a potent chemoattractant for both cell types. These data support a context-dependent role for CXCL8 expression in the CNS in which it may drive recruitment of NSC and OPC to sites of inflammation, but as a side-effect could also contribute to the failure of myelin repair in MS. © 2011 Wiley-Liss, Inc.