Why does your car stall when you depress the clutch when stopping?

Why does your car stall when you depress the clutch when stopping?
If your car runs fine cruising, then coming to a stop (perhaps at an off-ramp) you press the clutch, let off the gas, and the car stalls, then most likely, you have a vacuum leak from your intake manifold or low fuel pressure.This is dependent on the vehicle, of course. More information would have been more helpful in answering the question.