This paper will present a definition of Sensitometry in Computerized Tomography and discuss practical techniques used to determine relative CT sensitometry. Several factors that influence CT sensitometry are: (1) the x-ray beam spectral distribution, (2) the composition of the sample materials, (3) volume averaging, and (4) spatial nonuniformity of the scan field including the x-ray intensity distribution within the sample volume. Examples of comparative sensitometry among several CT units is presented as well as discussion of a technique for obtaining a continuous rather than discrete output.