There has been no clear consensus on the assessment and treatment of vitamin D deficiency prior to the publication of the National Osteoporosis Society (NOS) Vitamin D Guideline in 2014. The aim of our study was to assess the practice in a medicine for the older person day hospital setting relative to this guideline. A 6-month retrospective analysis of all new patients who attended service from January to July 2013 was carried out. Seventy-six patients were included in the final analysis. Mean age was 83 years. 39 (51%) patients had sufficient levels while 37 (49%) patients had insufficient levels; 14 (19%) being inadequate and 23 (30%) deficient. Eighteen patients who had insufficient levels were subsequently prescribed supplements; 13 (72%) received vitamin D3 in combination with calcium while 5 (28%) received vitamin D3 alone. Based on the findings of this study, we have made some recommendations and adopted the guideline