A longitudinal guide for motor vehicle seats having a bottom rail and a seat rail that are displaceable with respect to each other in one longitudinal direction. The motor vehicle seats are adjustable in a longitudinal direction and are also removable from the longitudinal guide. Detents are formed in the bottom rail. The seat rail comprises a base part and a supporting part. The base part has at least one front and at least one rear transverse bolt, which cooperate with the detents. The base part is adjustable with respect to the supporting part between a lower position, in which the transverse bolts are not engaged with the detents, and an upper position, in which the transverse bolts engage detents. Only in the lower position is the seat rail displaceable with respect to the bottom rail.