such as craniorachisis and exencephaly. One of the processes is changing in lamina neuralis cells shape, which is caused by actin microfilament rearrangement within lamina neuralis cells. To examine the distribution of actin microfilament during cranial neurulation Wistar rats embryo were used. Embryos were obtain at following days of development; 8 days 18 hours, 9 days, 9 days 6 hours, 9 days 12 hours, 9 days 18 hours, and 9 days 20 hours respectively. Immunohistochemistry Avidin Biotin-peroxidase Complex (ABC) method was used to examine and identify the distribution of actin in lamina neuralis cells. Light microscopic observation shows positive reaction for actin immunoreactivity in the apical surface of bending lamina neuralis cells. In contrast, actin is not observed in nonbending lamina neuralis. Actin is not detected at 8 days 18 hours embryos. At 9 days embryos, positive reaction is observed over the entire apical surface of lamina neuralis. Key words: Cranial neurulation, Actin, lamina neuralis, Rats embryo.