Despite the ability of infants to synthesize vitamin D through exposure to sunlight, nutritional rickets occasionally develops in infants even in areas with perennially sunny climates. In San Diego, a 1-year-old breast-fed infant presented with classic signs of nutritional rickets. Unsupplemented breast milk, limited exposure to sunlight, and darkly pigmented skin were predisposing factors. Because of this occurrence, we conducted a survey of vitamin supplementation practices among pediatricians in San Diego. Twenty-nine percent of 160 respondents do not prescribe vitamin D supplements for breast-fed infants. Those in practice less than ten years were even less likely to prescribe a vitamin supplement compared with their older colleagues. The patient report, coupled with a literature review, suggest the need for vitamin D supplementation for all nursing infants.