A circuit defect exists in four-bar linkages when a linkage cannot pass through all the design positions without being disassembled and reassembled in a different configuration. This paper describes a new and efficient procedure to rectify circuit defects in four-bar linkages at the synthesis level prior to the analysis level. It is achieved by controlling the change of sign of one of the angles opposite to the shortest link. The procedure utilizes the algebraic method where special points are employed to eliminate the solutions with circuit defects as a function of the design positions. Complete rectification is accomplished at the mid-synthesis level by controlling the critical angles of the linkage that identify the existence of circuit defects. This accounts for the rectification of circuit defects at the synthesis stage.