The measurement of regional blood flow (RBF) by means of the radioactive microsphere method yields large sets of raw data. In order to display this large volume of data, we have developed a program which provides the user with a graphical illustration of RBF in different organs (e.g., heart, kidney, brain) using various projections and sections. RBF is visualized by a pseudocolor representation. This set-up enables the user to perform a semiquantitative analysis of RBF and provides a tool for the compact representation of the spatial distribution of RBF values in different parts and layers of the organs being studied. The program runs on a standard microcomputer.