The invention relates to a method of assembling an opening leaf with a vehicle chassis, comprising the steps of measuring geometric references on the contour of an opening in a vehicle chassis, supplying an opening leaf corresponding to the opening in the chassis, adjusting at least one hinge secured to the chassis and to the opening leaf, according to references measured on the opening, assembling the opening leaf with the chassis using the adjusted hinge. The invention allows a door to be assembled with a vehicle precisely and in a minimum number of steps.