We report the depolarization of light scattered by a variety of birefringent and nonbirefringent tissues. We used Stokes polarimetry to investigate how scatterer structures in each tissue contribute to the depolarization of linearly versus circularly polarized light propagating through that tissue. Experiments were performed on porcine blood, fat, tendon, artery, and myocardium. The results indicate that the two incident polarization states are depolarized differently depending on the structure of the sample. As seen in sphere suspensions, for tissues containing dilute Mie scatterers, circularly polarized light is maintained preferentially over linearly polarized light. For more dense tissues, however, the reverse is true. The results illustrate situations where polarized light will provide an improvement over unpolarized light imaging, information that is crucial to optimizing existing polarimetric imaging techniques. © 2002 Society of Photo-Optical Instrumentation Engineers.