Background: Pemphigus vulgaris (PV) is a rare autoimmune blistering disease of the skin and mucous membranes. Because vitamin D deficiency is associated with many immune disorders, we compared the levels of vitamin D between PV patients and healthy controls. Methods: Vitamin D level of 20 patients with PV was compared with 20 healthy individuals matched for age, gender, hours spent in the sun, body mass index (BMI) and daily vitamin D intake at the same time interval. The severity of the disease was estimated according to ABSIS score. The serum level of 25-hydroxyvitamin D (25OHD) was measured by a commercial ELISA test. Results: Vitamin D deficiency in the pemphigus vulgaris group (75%) was higher than healthy controls (45%) (P = 0.053). Mean level of vitamin D in PV patients was significantly lower than healthy controls, and was in the range of vitamin deficiency (P ? 0.05). No significant relationship was observed between the severity of the PV disease and vitamin D levels (P > 0.05). Conclusions: Based on the results of the present study, the mean level of vitamin D in patients with PV was significantly lower than healthy people. Based on our findings and given the important role of vitamin D in preventing inflammatory and autoimmune diseases, vitamin D deficiency can be considered as a factor triggering the onset of PV.