Vitamin D deficiency has become a very contentious issue in the medical community. Inconsistent recommendations from various medical associations as well as lack of good quality rigorous studies further contribute to the confusion. Highly anticipated report by the Institute of Medicine published in 2011 failed to answer critical questions about the role of vitamin D for nonskeletal health. Unanswered questions about the long-term safety and benefits of vitamin D supplementation remain. This article attempts to summarize the existing evidence about vitamin D and provide the reader with information about the appropriateness of vitamin D supplementation for both skeletal and nonskeletal health. Controversy surrounding the issue of establishing the current standards for measuring vitamin D as well as the definitions and cut points for “deficiency” and “insufficiency” of vitamin D are explored. The role of poor health in relationship to vitamin D status is suggested as a possible contributing factor for growing prevalence of vitamin D deficiency.