The objective of this study was to evaluate the effect of structured post-discharge telephone follow-up (TFU) on the time to the first postoperative clinic visit and early unplanned hospital readmissions in patients after congenital heart surgery. Structured phone calls delivered by senior surgical practitioners were made 1–4 days post-discharge. Demographics and clinical outcomes of pediatric patients receiving a TFU from 2012 to 2014 were assessed. In total, 196 phone calls were made in 165 patients. Thirty-four health problems were identified in 32 (19 %) patients (15 infants, 9 children, 8 neonates). Sixty-nine percent (n = 22) of the patients with problems identified at TFU were males. Fifty-three percent (n = 17) of the patients with problems identified at TFU were RACHS 2. Most of the problems (53 %) were identified in middle-class economic families. Gastrointestinal and incision site complications were the most common problems identified. Eighteen (56 %) patients had adjustments of medications. Six (19 %) TFUs resulted in earlier than scheduled post-op clinic visits. Overall incidence of unplanned readmissions was 16 % and similar between the patients that had problems during TFU (13 %) and patients that did not have problems identified at TFU (18 %; p = 0.50). Our study demonstrates the potential impact of the timely and structured post-discharge TFU in identifying post-discharge complications and modifying discharge instructions. When TFU identifies a problem, the interventions may be successful in preventing readmissions before first postoperative clinic visit. TFUs may be helpful, as a supplement standard of care with specific focus on patients <1 year of age to help identify adverse events that could otherwise escalate.