We present a general method for worst-case limit kinematic tolerance analysis: computing the range of variation int he kinematic function of a mechanism from its parat tolerance specifications. The method covers fixed and multiple contact mechanisms with parametric or geometric part tolerances. We develop a new model of kinematic variation, called kinematic tolerance space, that generalizes the configuration space representation of nominal kinematic function. Kinematic tolerance space captures quantitataive and qualitative variations in kinematic function due to variations in part shape and part configuration. We derive properties of kenematic tolerance space that express the relationsip between the nomical kinematics ofmechanisms an their kinematic tolerance space computation algorithm for planar paris with two degrees of freedom.