1. Intestinal calcium and phosphate absorption have been measured in nine patients with nephrotic syndrome and normal renal function, by a combined radioisotope technique which allows simultaneous measurement of both quantities. The values obtained were compared with those obtained in 20 normal controls.
2. Calcium absorption in the nephrotic group was significantly lower than in the control group (P < 0.01), but phosphate absorption in the nephrotic group did not differ from controls.
3. This dissociation between calcium and phosphate absorption provides further evidence for independent mechanisms governing the two absorption processes.