Psoriasis is a chronic, genetic, non-contagious skin disorder that appears in many different forms and can affect any part of the body, including the nails and scalp. It may affect the quality of life by causing psychosocial stress. Psoriatic arthritis (PA) is considered to be a spondyloarthropathy, and has spinal and peripheral joint involvement associated with psoriasis. The purpose of this study was to evaluate the prevalence of signs and symptoms of temporomandibular disorders (TMD) in patients with psoriasis without PA and in patients with PA and compare with a healthy group. Signs and symptoms of TMD were evaluated by means of Helkimo's Anamnestic (Ai) and Dysfunction indices (Di). In the present study, patients with psoriasis without arthritis did not report TMD signs and symptoms significantly more often than healthy subjects. A statistically significant increase was found in patients with PA when compared with psoriasis patients without arthritis and healthy patients in Di. In patients with PA, muscle tenderness on palpation, temporomandibular joint sounds and stiffness/tiredness in jaws in the morning were the most frequent findings. It is concluded that the signs and symptoms of TMD in PA is caused mainly by related joint involvement that directly affects the masticatory system.