This brief presents a novel algorithm for optimizing the design of infinite-impulse response (IIR) switched.capacitor (SC) decimators. It is implemented with a computer-assisted iterative methodology to achieve minimum capacitance spread and usually leading also to the minimization of the total capacitor area, while considering scaling for maximum signal handling capability. A linear/nonlinear programming method is adopted for optimum adjustment of the capacitance values, within a specific decimator structure and a finite number of iterations. Several examples of automatic and optimum design of second-order IIR SC decimators are presented, together with a comparison against previous designs, obtained for the same circuits through the use of traditional methods.