Introduction Multiple myeloma (MM) causes generalized bone loss leading to lytic bone lesions and pathologic fractures. The increased osteoclast activity and reduced osteoblast function favors bone resorption and decreased bone formation. Vitamin D is vital in regulating calcium homeostasis and osteoclast-mediated bone resorption. Defi ciency of Vitamin D among MM patients may complicate bone mineralization problems and fractures. Objective General Objective To determine the status of Vitamin D in patients with multiple myeloma Specifi c Objective To determine the levels of Vitamin D, intact parathyroid hormone and ionized calcium among MM patients Methodology This is a prospective, cross-sectional study which included patients who were 18 years old and above, male or female, diagnosed with MM at the University of Santo Tomas Hospital, with or without treatment. Excluded in the study were those with Vitamin D and calcium supplementation. Eligible subjects were extracted blood for Vitamin D assay, intact parathyroid hormone and ionized calcium. Results A total of 22 patients with MM were included in the study. Sixteen patients (72.7%) had hypovitaminosis D. Among these sixteen patients, seven (31.8%) had Vitamin D defi ciency (Vitamin D levels <20 ng/mL [50 nmol/L]) and nine (40.9%) had Vitamin D insuffi ciency (levels of 21-29 ng/ mL [52.5-72.5 nmol/L]). Only 6 (27.3%) of them were found to have normal serum Vitamin D (levels of >29 ng/mL [>72.5 nmol/L]). The mean age (p=0.069), intact PTH (p=0.062) and ionized calcium (p=0.188) of the three groups of patients did not differ. Conclusion This study found a high incidence of Vitamin D defi ciency among MM patients seen at the University of Santo Tomas Hospital. Vitamin D defi ciency was independent of age, intact PTH and ionized calcium. It was more common in male subjects. Patients with hypovitaminosis D are at risk of having secondary hyperparathyroidism. Recommendation Vitamin D status should be determined among patients with MM. Early recognition and treatment of hypovitaminosis D will prevent the risk of having secondary hyperparathyroidism that can complicate skeletal-related events.