We describe a simple modification to a confocal microscope, which analyses the state of polarization of light emerging from the specimen so as to permit quantitative polarized light microscopy to be performed. The system uses a novel form of rotating analyzer which, together with lock-in detection, permits images to be obtained where the image contrast corresponds to both specimen retardance and orientation (e.g. in the case of a birefringent specimen). Images are presented from a wide range of specimens and the origin of the contrast observed from simple point scatterers is investigated both theoretically and experimentally.