In biological specimens of 150 nm and greater, inelastic scattering typically surpasses elastic scattering in magnitude. Because of the chromatic aberration of the objective lens of a TEM, the inelastically scattered electrons are focused differently, resulting in a loss of contrast in an ordinary TEM. With energy filtering, however, the inelastically scattered electrons can be prevented from contributing to the image, resulting in substantial recovery of contrast. In very thick specimens (1-5 μm), an energy filter can be used to select electrons of a particular energy loss, and an image with usable contrast can be formed. Further, by imaging only with electrons that have experienced characteristic energy losses, information can be obtained about the spatial distribution of various elements in the sample.Because of presently available instrumentation, energy filtered biological TEM has so far only been performed with TEMs of primary energies of 120 keV and lower. In this paper, we demonstrate the feasibilty of obtaining interesting biological information with a newly developed imaging filter designed for operation at up to 400 kV.