In this paper a model of MOS transistor mismatch based on autocorrelation function of the statistical parameters is proposed. Firstly a statistical model which maps the statistical behavior of technological parameters considered as a source of errors, into the behavior of device parameters, which depends on device geometry (area and layout) and mutual distances between devices, is derived. Then particular forms for the autocorrelation function are proposed so that expressions for the parameter mismatch variance can be obtained. The model has also been used to analyze mismatch effect on interdigitated and cross-coupled structures.