The identification of intermediate filaments within immature cells is valuable as a means to investigate neuronal and glial differentiation. The purpose of this study is to investigate the time of appearance of neuron and glia within rat embryo by identifying cell-specific intermediate filaments. Pregnant rat were daily sacrificed from day 9-20 of pregnancy. Rat embryos were fixed with 100% ethanol and then we have made the paraffin section. We have stained the specimens for vimentin in accordance with ABC method and for GFAP in accordance with PAP method. We have performed Bodian stain. The neural plate of day 9 rat embryo is composed with vimentin positive immature cells which are disposed with pseudostratified arrangement. In midbrain of day 13 rat embryo, immature cells and their fibers are vimentin positive which are spanning from ventricular surface to marginal layer. NFP is detectable in immature cells and fibers of marginal layer. But GFAP positive cells and fibers are not identified in the same region. In anterior column of day 18 rat embryo, GFAP positive fibers are detectable. Summarizing of these results, we can display first: immature cells composing of neural plate are vimentin positive at day 9, second: NFP positive fibers and cells appear at day 13, third: NFP positive cells are vimentin positive, too, forth: GFAP positive fibers appear at day 18 and they are vimentin positive, too.