The radiological findings in 14 female patients with the loin plain--haematuria syndrome are described. The abnormal features are found on renal arteriography, the changes being bilateral in 13 of the 14 patients. In the smaller branches of the arterial tree there are changes of irregularity, tortuosity, stasis, and occlusion. Although not all these changes are present in every patient, the nephrogram is always abnormal, with multiple small defects in the renal cortex and blurring of the corticomedullary differentiation. It is expected that this syndrome will become more widely recognised.