We present two cases of vitamin D-dependent rickets type II, a rare disease caused by a hereditary disorder of the receptor for 1,25 dihydroxyvitamin D (1,25 (OH) 2 D). The first patient was seen for the first time at the age of 2 years with florid rickets, almost complete alopecia, and an elevated plasma level of 1,25 (OH) 2 D; there was no improvement following treatment with 1 alpha-hydroxy-vitamin D3). The second patient, a boy whose parents are first cousins, was seen at the age of 7 years with severe rickets, partial alopecia and an elevated serum level of 1,25 (OH) 2 D; the rickets disappeared after administering high doses of 1 alpha hydroxyvitamin D3 and vitamin D.