Nestin was originally cloned from the central nervous system of rat embryos. Its expression was found primarily in neuroepithelial stem cells and proliferating neural progenitor cells. The expression of nestin can also be found in the parenchyma. In developing murine embryos, nestin expression coincides with the onset of neurulation and is dramatically down-regulated in mature neural cells. Nestin is conserved across diverse species including mammals, chicken and zebrafish. Phylogenetic analysis reveals that the predicted amino acid sequence of Cisapride zebrafish nestin is clustered with the mammalian nestin orthologue. Furthermore, similar to mammals, zebrafish nestin is expressed widely in developing nervous system and its expression is restricted to neural proliferation zone in adult fish. Despite extensive investigations to ascertain nestin as a marker of neural stem and progenitor cells, the functions of nestin are not clearly understood. Recent reports suggest that nestin may be involved in positioning and functioning of subcellular organelles and may serve as a scaffold for kinases that regulate diverse cellular functions such as proliferation, survival and differentiation. However, it is unclear whether nestin is important in neural development. In this study, we evaluated the function of nestin in zebrafish embryogenesis by injecting nestin morpholino into fertilized eggs. Nestin MO treatment resulted in brain and eye developmental defects. These developmental 6-Acetamidohexanoic acid defects were accompanied by reduction in NPCs and increase in neural and retinal apoptosis. Nestin is a hallmark of NPCs. Its expression in zebrafish embryos was first detected about 13 hpf and spread all over the brain and the spinal cord by 24 hpf. Nestin expression during this period of zebrafish embryo development may be critical for brain development. The findings reported here indicate that nestin is indeed essential for zebrafish brain and eye development. Knockdown of nestin in zebrafish embryo by morpholino injection causes distinct morphological changes characterized by small head, small eyes and overt hydrocephalus.