Objective:to evaluate the efficacy and safety of a selective phosphodiesterase type 4 inhibitor in patients with psoriasis and psoriatic arthritis (PsA).Subjects and methods.An open uncontrolled study was conducted, which enrolled 20 patients (12 men, 8 women); their mean age was 39.2±14.3 years, the mean duration of psoriasis and PsA was 20.2±12.2 and 10.4±10.2 years, respectively. All the patients included in the study had previously received phototherapy, systemic drugs (methotrexate, aromatic retinoids) with an insufficient effect. Apremilast was administered according to the standard regimen: dose titration during the first 5 days, then 30-mg tablets twice daily for 26 weeks. The efficiency of the therapy was evaluated from changes in PASI, BSA, and sPGA and according to the American College of Rheumatology (ACR) criteria at 14 and 26 weeks and from those in DAS28 at 26 week.Results and discussion.There were 50 and 75% decreases in PASI respectively in 12 (60%) and 5 (25%) patients, at week 14 of therapy and in 14 (70%) and 7 (35%) patients at week 26. Fourteen (81.2%) patients achieved 20% ACR improvement at week 14. DAS28 decreased on an average by 1.8 at week 26. Adverse events (severe headache, tachycardia) were observed in two patients who were excluded from the study.Conclusion.Apremilast is an effective and safe agent for the treatment of psoriasis and PsA in patients who have received another systemic therapy proven to be ineffective or they tolerated the latter poorly.