Serial renal ultrasonography was performed in 50 consecutive neonates with birth weights less than 1200 gm who survived to at least 3 weeks of age. Nephrocalcinosis developed in 8 (67%) of 12 white and only 6 (16%) of 38 nonwhite infants (p < 0.01). Seven (78%) of nine infants with a family history of kidney stones had nephrocalcinosis compared with only 7 (17%) of 41 without a family history of kidney stones (p < 0.001). We conclude that nephrocalcinosis in our population of very low birth weight neonates is significantly and independently associated with a family history of kidney stones and white race.