Improved results have evolved from the modified Norwood procedure (NP). This study compares the incidence of interventions after NP with the Sano (n = 37) and modified Blalock–Taussig (BT n = 70) shunt. Incidence, location, interval of interventions, and weight were retrospectively analysed for 107 neonates undergoing NP during the period from October 2002 to December 2009. Forty-six (43.0 %) patients underwent interventions, mostly for dilatation of the aortic arch ([DAA] n = 26 [24.3 %]; Sano n = 10, BT n = 16, p = 0.6), dilatation of the shunt ([DS] n = 15 [14.0 %]; Sano n = 11, BT n = 4; p = 0.002), or closure of aortopulmonary collaterals ([APC] n = 15 [14.0 %]; Sano n = 3, BT n = 12; p = 0.08). Mean interval after NP and body weight at DAA, DS, and APC were 72.4 ± 18.9, 108.5 ± 15.8, and 110.7 ± 17.8 days and 4.5 ± 1.3, 4.9 ± 1.9, 5.3 ± 1.2 kg, respectively. The interventions were not associated with mortality but with a greater rate of complications (9 of 46 [21.4 %]) compared with the rate after diagnostic catheterization (0 of 45, p = 0.03). Complications included closure of the femoral or subclavian artery (n = 5), cerebral embolic or bleeding events (n = 4), cardiopulmonary resuscitation (n = 3), and temporary heart block (n = 2). Actuarial survival was similar from the postoperative month 8 onward at 78.6 ± 4.9 % (95 % confidence interval [CI] 67.0–86.5 %) for Sano and 78.4 ± 6.8 % (95 % CI 61.4–88.6 %) for BT (p = 0.95). Interventions after NP were common irrespective of shunt type. However, a significantly greater rate of shunt interventions was noted in the Sano group. In particular, interventions addressing the aortic arch and the shunt were related with a significant rate of complications.