The crank-rotatibility synthesis of single degree-of-freedom mechanisms is investigated. This synthesis problem may be defined to be the determination of the allowable dimensions of a mechanism such that a desired link can act as a crank. The developed synthesis algorithm yields, analytically, sufficient conditions for crank-rotatibility. These conditions are in the form of inequalities that involve the dimensions. The method is applicable to any planar or spatial mechanism, for which an appropriate input-output equation may be derived. The algorithm can be used to determine the limit positions of any link in the mechanism.