A new roentgenographic classification of renal cystic disease is presented. The disease entities are grouped into 4 types depending upon their pyelographic features. In Type I the contrast material can be seen in dilated collecting tubules. In Type II no functioning renal tissue is present in the area of cyst formation which may involve only a portion of the kidney. The cysts may distort the renal outline and collecting system. Type III is characterized by cyst formation intermixed with areas of functioning tissue. Pyelography shows distortion of the collecting system by the multiple cysts. In Type IV the actual small cysts are not demonstrated by pyelographic study, but the obstruction of the lower urinary tract is shown by cystography. The cystic disorders are briefly discussed, correlating the roentgenographic findings with the pathologic anatomy.