Neuroglobin (NGB) is a newly discovered member of the hemoglobin family that reversibly binds O₂ and is expressed predominately in vertebrate brain. NGB is a monomer composed of 151 amino acids, with high oxygen affinity. It is of ancient evolutionary origin. Hithertos, it has been proved to associate with oxygen storage, transport and neuron protection. NGB gene expression is mediated by at least 2 signal transduction pathways. The discovery of NGB provides a new direction for treating patients with strokes and other hypoxia-related diseases.