The purpose of this review is to examine the current literature regarding calcium and Vitamin D deficiencies in vegan diets and the possible relationship to low bone mineral density and incidence for fracture. Prominent databases were searched for original research publications providing data capable of answering these questions: (i) Do vegans have lower-than-recommended levels of calcium/Vitamin D? (ii) Do vegans have lower bone mineral density than their non-vegan counterparts? (iii) Are vegans at a greater risk for fractures than non-vegans? The findings gathered consistently support the hypothesis that vegans do have lower bone mineral density than their non-vegan counterparts. However, the evidence regarding calcium, Vitamin D and fracture incidence is inconclusive. More research is needed to definitively answer these questions and to address the effects of such deficiencies on the medical and socioeconomic aspects of life.