<p class="abstract"><strong>Background:</strong> Ustekinumab is a biological agent used in the treatment of psoriasis. This study evaluated the treatment response of psoriasis patients who received ustekinumab.</p><p class="abstract"><strong>Methods:</strong> The study included nine patients with plaque-type psoriasis who received ustekinumab treatment. Clinical response of all patients was evaluated with psoriasis area and severity index (PASI), dermatology life quality index (DLQI), and

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... sis disability index (PDI) at 0, 4, 16 and 28 weeks. The patients were also evaluated for metabolic syndrome and its effect on treatment response.<strong></strong></p><p class="abstract"><strong>Results:</strong> A total of five male and four female patients with psoriasis vulgaris were included in the study. At the end of 28th weeks, 55% of the patients reached PASI 75 score. The mean PASI scores of the patients at weeks 0, 4, 16, 26 and 28 were 36.98±12.28, 8.86±9.06, 9.52±11.55, 3.55±3.61 and 6.98±6.40, respectively. Although not statistically significant, at the 28th weeks, the mean PASI, DLQI and PDI values of the patients with metabolic syndrome were higher than those without metabolic syndrome (p=0.505, p=0.314, p=0.786, respectively).</p><p class="abstract"><strong>Conclusions:</strong> Ustekinumab is an effective treatment option for patients with psoriasis who resistant to conventional and biological treatments. In resistant cases to the ustekinumab, the routine treatment interval should be reduced. Psoriasis patients with accompanying metabolic syndrome may have a lower response rate than those without metabolic syndrome to biological agents.</p>