An upper rack vertical adjustment system for a dishwasher, including an upper rack first portion, and an upper rack second portion rotatably attached to the first portion to selectively create an opening in the bottom of the rack to provide clearance for items placed in the lower rack. For adjusting the height of the upper rack, a slidable member has two elongated arms extending therefrom each having a wheel attached at an end of the arms is provided on each side of the rack. For each slidable member, a plate is mounted to a portion of the upper rack and the said slidable member is pivotally mounted to the plate. A locking mechanism locks the slidable member in one of several predetermined positions.