en تخصصي Special پژوهشي Research <strong>Objective:</strong> Psoriasis is an inflammatory disease of the skin and the joints. Psoriatic patients sometimes suffer from vitamin D deficiency and hypocalcemia. The aim of our study was to evaluate the level of calcium and vitamin D in patients with psoriasis.<br> <strong>Materials and Methods</strong><strong>:</strong> In this analytical cross sectional study, 110 cases of psoriasis that were referred to Shohadaye Mehrab clinic during 2015 and 110 non-psoriatic patients enrolled. Serum levels of calcium, phosphorus, parathyroid hormone (PTH), alkaline phosphatase (ALK) and 25- hydroxy vitamin D₃ [(25OH) D₃] were measured in both groups. Data were analyzed using SPSS software version 19. Chi square test and T-test were used for statistical analysis.<br> <strong>Results:</strong> Among110 patients with psoriasis 74 (67.3%) were men and 36 (32.75%) were women. There was no significant difference in the serum level of calcium (<em>P</em>-value: 0.563), phosphorus (<em>P</em>-value: 0.381), PTH (<em>P</em>-value: 0.364) and ALK (<em>P</em>-value: 0.639) between two groups. Vitamin D deficiency was found in 64.5% of psoriatic patients and 60% of the controls (<em>P</em>-value= 0.45); However 30.9% of psoriatic and 17.3% of the controls suffered from severe hypovitaminosis D. This difference was statistically significant (<em>P</em>-value= 0.014).<br> <strong>Conclusion</strong><strong>:</strong> We found a significant relationship between severe hypovitaminosis D and psoriasis. This finding revealed the need for evaluation of psoriatic patients for the presence of vitamin D deficiency. Psoriasis, Vitamin D, Calcium, Parathyroid hormone 151 155 http://ijdo.ssu.ac.ir/browse.php?a_code=A-10-30-287&slc_lang=en&sid=1 Mohammad Ebrahimzadeh Ardakani 0000-0002-9581-5100 Yes Department of Dermatology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Mohammad Afkhami-Ardekani 0000-0001-9768-5904 No Yazd Diabetes Research center, Shahid Sadoughi University of Medical Sciences Yazd, Iran Mohammad Reza Taghizadeh Yazdi 0000-0002-9018-2703 No Departments of Industrial Management, University of Tehran, Tehran, Iran Nasim Namiranian 0000-0002-5133-6204 No Yazd Diabetes Research center, Shahid Sadoughi University of Medical Sciences Yazd, Iran Farideh Radmehr No Department of Dermatology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran