The use of polarization-sensitive sensors is being explored in a variety of applications. Polarization diversity has been shown to improve in a significant way the performance of the automatic target detection and recognition. However, it also brings out the problems associated with processing and storing more data and the problem of calibration of the polarimetric sensors themselves and the problem of dealing with polarimetric sensors on board of maneuvering platforms. In this paper, we present techniques for extracting attributes that are invariant to the polarization transformation. The polarimetric target signatures are represented in terms of the components of the Jones vectors. The cases associated with active radar and passive infrared polarimetry are considered. For the radar, two algebraic expressions, functions of the radar cross sections, exist that are invariant under any linear transformation of the basis of the polarization. In the infrared case, invariant algebra is used to extract the target-related attributes that are invariant to the affine transformation of the polarization coordinate system.