BACKGROUND: Nail psoriasis is common in patients with psoriasis and can seriously affect their quality of life. Current treatments are limited and there is no standard course of therapy. OBJECTIVES: To assess the efficacy and safety of etanercept (ETN) on nail psoriasis in patients with moderate-to-severe psoriasis. METHODS: Patients with moderate-to-severe plaque psoriasis, who had previously failed at least one form of systemic therapy for nail psoriasis, were randomized to receive open-label ETN 50 mg twice weekly (BIW) for 12 weeks followed by once weekly (QW) for 12 weeks (BIW/QW group) or ETN 50 mg QW for 24 weeks (QW/QW group). The primary endpoint was the mean improvement in the Nail Psoriasis Severity Index (NAPSI; score range 0–8) over 24 weeks in the target fingernail with the most severe abnormalities. RESULTS: Seventy-two patients received one or more doses of ETN (38 BIW/QW; 34 QW/QW) and 69 patients were included in the modified intent-to-treat population. At baseline, mean (standard error) target fingernail NAPSI score was 6·0 (0·3) in the BIW/QW group and 5·8 (0·3) in the QW/QW group. At week 24, mean target fingernail NAPSI score had decreased significantly by −4·3 [95% confidence interval (CI) −4·9 to −3·7; P < 0·0001] in the BIW/QW group and by −4·4 (95% CI −5·0 to −3·7; P < 0·0001) in the QW/QW group. Improvement in NAPSI showed significant correlation with Psoriasis Area and Severity Index improvement. ETN was well tolerated with no unexpected safety findings. CONCLUSIONS: Both ETN regimens were effective at treating nail psoriasis in this patient population. WHATʼS ALREADY KNOWN ABOUT THIS TOPIC?: WHAT DOES THIS STUDY ADD?