The non-linearity of silicon capacitive pressure sensors with a single-sided island-diaphragm structure and a diode-quad interface circuit is investigated. Based on the mathematical analysis of the sensor non-linearity, two types of linearization approaches have been developed. The first one uses feedback from the output to control the excitation voltage and, thereby, to adjust the non-linearity of a conventional structure sensor (consisting of a sensitive capacitor and a reference capacitor) conveniently to 0.1% or smaller. Another approach uses a novel push-pull capacitive structure, in which a pair of pressure-sensitive capacitors is operated in a push-pull configuration. The output is inherently linear if there is no parasitic capacitance. For a practical device with parasitic capacitance comparable with the working capacitance, the nonlinearity is usually of the order of 0.1%. The experimental results show that the linearity is improved by at least one order of magnitude by using either of the two approaches.