Abstract: AIM: To analyze the risk factors for prolonged stay in intensive care unit (ICU) after corrective surgery for tetralogy of Fallot (TOF). METHODS: Between January 2007 and June 2008, 329 consecutive patients with TOF undergoing corrective surgery were divided into two groups based on the length of stay in ICU. Prolonged stay in ICU was defined as 7 days or more. Group I was comprised of 284 patients with no prolonged ICU stay. Group II was comprised of 45 patients with prolonged ICU stay. Uni- and multivariate analysis were used to identify risk factors. RESULTS: Univariate analysis showed that group II subjects were younger and the Nakata index was lower compared with those in group I. Ventilation time, bypass time, clamping time, presence of transannular patch and rate of infection were longer or higher in group II than in group I. Logistic regression showed that risk factors for prolonged ICU stay were age ≤6 months, Nakata index <140 mm2/m2 and cardiopulmonary bypass time >150 min. CONCLUSION: Prolonged ICU stay after corrective operation of TOF can be predicted by risk factors. Patients with these risk factors require more pre- and postoperative care to reduce mortality and morbidity and to avoid prolonged postoperative ICU time.