Objective: The aim of this study is to investigate the relation between vitamin D levels, vertebral defoi functional status, quality of life, acute phase reactants and enthesopathy in patients with psoriatic arthritis (PsA). Patients and Methods: Fifty-two patients with PsA and 52 controls were enrolled to the study. Routine blood tests and serums 25-(OH)D3 were measured. The thoracic and lumbar vertebrae deformities identified in the radiographies were evaluated by a radiologist. Psoriatic Arthritis Quality of Life (PSAQoL) was used for evaluating quality of life and disease activity parameters for PsA were assessed. In PsA patients, correlations was performed between the 25(OH)-D3 levels and PGA (patient global assessment), PhGA (Physician global assessment), tender JC (joint count), HAQ-S (Health Assessment Questionnaire for the Sp ondyloarthropathies), PSAQoL, MASES (Maastricht Ankylosing Spondylitis Enthesitis Score) and BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) values. Results: The results showed that 25(OH)-D3 levels was not correlated with these values. (p>0.05 for r = -0.171, r = -0.167, r=-0.069, r=-0.236, r=-0.062, r= -0.058 and r = -0.106 respectively). It was determined that the PSAQoL score had a positive and statistically significant correlation with the PGA, swollen JC, CRP, HGD, tender JC, VAS -pain, HAQ-S, MASES and BASDAI values in PsA patients. (p>0.05 for r=0.291, r=0.324, r=0.346, r=0.312; and p=0.001 for r=0.472, r=0.380, r=0.565, r=0.696, r=0.359, r=0.633, respectively) Statistical analyses demonstrated that PsA patients with vertebral deformities had higher numbers of tender joints, more prolonged periods of morning stiffness, higher DAS28-ESR (Disease Activity Score) scores, and higher levels of vitamin D (p<0.05, p<0.05, p=0.05 and p<0.05, respectively). The multiple logistic regression analysis indicated that the only factor which had an effect on the development of vertebral deformities was the use of steroids. Conclusions: This result has demonstrated that psoriatic arthritis has a considerable effect on patient quality of life. Most significant factors that affecting quality of life were physical pain and disability while vertebral deformities and 25-(OH)D3 had no significant effect.