Objectives: We evaluated the effectiveness and reliability of percutaneous closure of persistent arterial duct (PAD) with the Amplatzer Duct Occluder II (ADO II), together with short- and mid-term results. Study design: The study included 16 patients (10 girls, 6 boys; median age 6 years; range 5 months to 12 years) who underwent percutaneous PAD closure with the ADO II device. The ductus diameter was less than 6 mm in all the cases. According to the Krichenko classification, 10 patients had type A, five patients had type E, and one patient had residual PAD. The patients were assessed by aortography and echocardiography. The mean follow-up was 13.9 months (range 2 to 23 months). Results: Closure of PAD was successfully performed via the arterial approach in all the patients. The median ductus waist diameter was 3 mm (range 2 to 5 mm), the median device waist diameter was 4 mm (range 3 to 6 mm), and the waist length was 4 or 6 mm. The mean fluoroscopy time and the mean procedure time were 10.6 min (range 4 to 39 min) and 30 min (range 18 to 80 min), respectively. Immediate aortography following the procedure showed shunt only through the device lumen. No residual shunt or increases in aortic and left pulmonary flow velocities were observed in echocardiographic examinations. No complications occurred during the procedure and follow-up. Conclusion: In all the cases, the ADO II device was found effective and reliable for closure of PADs of less than 6 mm. © 2011 Türk Kardiyoloji Derneǧi.