Nutritional rickets, an ancient disease that was thought to have been cured in the early part of the 20th century, has made an unexpected comeback in recent years throughout the world. Although the frequency of its occurrence is poorly documented, increasing case reports of rickets are apparently related to low dietary intake of vitamin D and calcium and decreased sunshine exposure. Greater awareness of this problem is needed, as are further data regarding vitamin D status and incidence of rickets among infants and toddlers. Routine provision of supplemental vitamin D to all breastfed infants remains controversial, but may become more widely recommended.