Rickets is known as rare disease nowadays. Among 269.649 concerned clinic patients in 6 and one half years since 1965 to June 1971 at Yonsei Univ. Severance Hospital, there were 33 cases of various rickets with annual increasing rate since 1968. Compared to the 1965 and previous years to 1968 almost 5 times increase in number noted. The incidence of rickets was 8171:1 and ratio was 0.012 percent. There was none specific sex difference. The analysis of rickets disclosed vitamin D deficient type to be highest incidence of 90.9 %. The rest was 3.03 % each of vitamin D resistant rickets, renal rickets, and infantile tetany. Among 33 cases of rickets X-ray study was done in 24 cases of 72.2%. All showed positive rachitic bony changes. Blood chemistry disclosed elevated alkaline phosphatase generally byt serum phosphorus and calcium was supportive evidence for rickets due to overlap with other idseases of malabsorption, starvation andvomiting in low serum phosphorus even I high alkaline phosphatase differentiation should be made in fracture of bone, hyperparathyroidism and metastatic bone disease however these factor can be eliminated some extend to the age prevalence in childhood of rickets. In X-ray study of among 24 cases, 21 of knee joints disclosed metaphyseal ricketic bony changes. And 13 cases in wristsm, 11 in ankles, 7 in long bones and 12 in pelvis all show rachitic changes in 100 percent, however, in thoracic cage of 12 cases of half only disclosed rosary, and 2 looser zones. Therefore X-ray study still stands best aid for diagositic value in rickets.