Background: This study aimed to assess the outcomes of valve-in-valve implantation within previously placed bioprosthetic valves. Methods: This single-center retrospective study included patients who underwent percutaneous valve-in-valve procedures between July 2014 and September 2023. These patients had previously received pulmonary bioprosthetic valves via surgical or transcatheter methods. Results: The study included 20 patients (13 males, 7 females; mean age: 20.4±7.1 years; range, 10.8 to 35.8 years). Preprocedural assessment revealed stenotic dysfunction in 12 patients, regurgitant dysfunction in two patients, and a combination of both in six patients. Following implantation, there was a notable improvement in invasive measurements; systolic right ventricular pressure decreased from 64.0±24.5 mmHg to 31.3±6.7 mmHg (p<0.001), right ventricular outflow tract gradient from 44.0±23.2 mmHg to 7.6±5.8 mmHg (p<0.001), and echocardiographic pulmonary regurgitation grade from 2.1±1.2 to 0.2±0.4 (p<0.001). The median time between initial bioprosthetic pulmonary valve placement and valve-in-valve procedure was 8.2 years (IQR, 6.2 to 9.9 years). The median follow-up duration was 24.8 months (IQR, 8.3 to 40.2 months). Only one patient required a repeat PPVI procedure 10 years after the valve-in-valve procedure, while no other patients required reintervention during the follow-up period. Conclusion: Valve-in-valve implantation within previously placed bioprosthetic valves is a feasible and safe approach, offering symptom relief and eliminating the need for further surgical interventions.