Posterior fossa surgery (PFS) is one of the most complicated surgeries in the neurosurgery field. Asystole is a severe complication during this type of surgeries. Trigemino cardiac reflex (TCR) is hypothesized to stimulate the asystole. The case of a 40 year old female who established a cardiac arrest is reported when the surgeon was flooding the field with normal saline at the end of the surgery. A good knowledge of TCR is important and a close monitor should continue till the end of surgery.