In 85 patients with ascertained chronic pyelonephritis the relations between the measured values of the combined PAH-inulin-clearance, the index of the adrenal cortex and other radiological findings were investigated. Here the determination of the cortex of the adrenal cortex resulted in a better correlation with the sizes clarification values than the calculation of the size of the kidney. By variance analysis (F-test) significant differences between the individual function groups became clear.