Abstract: An inertia sensitive latch mechanism for preventing a motor vehicle seat back from folding from a normal upright position to a folded forward position when the seat is exposed to deceleration loads above a predetermined level including a pendulum pivotally mounted to the movable seat back having a notch and tooth for engaging a striker bar. The center of gravity of the pendulum is located such that when the seat back is urged from the upright position to the folded position when the vehicle is exposed to a predetermined deceleration load, the pendulum engages the striker bar to prevent movement of the seat back. The striker bar is movably mounted to the seat support and the latch mechanism includes a guide member adjacent the pendulum for moving the striker bar to a predetermined location relative to the pivot point of the pendulum as the seat back is moved into its normal upright position.