A technique for radiographic delineation of the microvasculature of the canine kidney is described. The renal vasculature was perfused (at a physiologic pressure) with a finely divided barium sulfate. Microangiograms of sagittal renal slices were produced, using a special radiography machine that allows low kilovolt peak, low milliamperage, and exposure times up to 5 minutes. A special high resolution film (800 lines/mm) was used. With this technique, it was possible to delineate interlobar, arcuate, and interlobular arteries, afferent arterioles, glomerular capillaries, and peritubular vessels. The kidney slices prepared for microangiography were undamaged and available for histochemical processing. Thus, the microvascularity was correlated with the histologic appearance of the renal tissues.