Background: Our institution mainly perform Norwood stage-I palliation for hypoplastic left heart variants and severe AS with VSD and/or single ventricle physiology and the survival improved over 85% in this decade. However, strict pulmonary blood flow control is indispensable for early to mid-term postoperative mortality and morbidity. After the palliation, we perform interventions to increase pulmonary forward flow as well as other techniques, as a bridge to next stage elective surgery. Study Population: Fifty-eight consecutive patients who underwent Norwood procedure since 1999 until 2008. HLHS and variants (n=30), and non-HLHS (n=23) are included. Results: Hospital death within 30 days after Norwood was 8/58, and among the 50 survivors, 20 patients (40%) were underwent intervention subsequently. The median age of Norwood, intervention, and the next stage surgery such as Glenn or Rastelli were 6-days, 5-months, 6-months old, respectively. Among the 20 interventions, 11 included dilatation of BT or RV-PA shunt by a balloon or a stent, and 8/11 included releasing of hemoclips primarily loaded for flow restriction. Coil occlusion for aorto-pulmonary collaterals was performed in 17/20 cases. High-pressure balloon angioplasty was successfully performed for coarctation of neo-Aorta in 7/20 cases. 15/20 cases recieved multiple interventions simultaneously. No procedural complications occurred, and 18/20 underwent next stage surgery with favorable postoperative course. Conclusions: Shunt dilatation including “declipping” procedure and occlusion of aortopulmonary collaterals were safe and effective in the aspect of pulmonary blood flow control, from restriction to promotion. Simultaneous multi-interventional procedures can be performed with minimal invasion in hemodynamically unstable infants.