Seventy-seven patients with nephrocalcinosis as revealed by X-ray studies over a 10-year period are reviewed. A programmed clinical and metabolic study was performed on each case; the author's criteria included the different pathogenic factors considered in the etiologic definition of the disease. There were 22 cases with primary hyperparathyroidism, 19 with spongy kidney, nine with tubulointerstitial nephropathy, five with hyperoxaluria, five with distal renal tubular acidosis, four with esential hypomagnesemia, and three cases of miscellaneous etiology (vitamin D intoxication, Fanconi's syndrome, Bartter's disease). Ten other cases were classified as idiopathic nephrocalcinosis since no definite cause could be found. The clinical characteristics (symptoms, associated diseases, diet and medication intake, family history) and the biochemical findings are analysed for each group. The physiopathologic mechanisms, comparisons between each etiologic group, treatment, clinical course, and prognosis are commented on. The conclusion drawn is that nephrocalcinosis is a clinical syndrome of various etiologies which in most cases arises from an underlying metabolic disease.