Introduction: Explicit outcomes routinely measured across the life span following hypospadias surgery, defined by a core outcome set (COS), will harmonize and overcome reporting heterogeneity. Methods: Age-specific outcomes identified in a literature review were presented in a threeround Delphi survey. Participants (professionals, parents, and patients) were encouraged to suggest outcomes in the first Delphi round. In subsequent rounds, participants were asked to choose and rank up to five preferred outcomes for each age. To be deemed core, an outcome needed over 70% of votes in a round. Results: Professionals were mainly paediatric urologists (rounds 1, 2, 3: n = 57 [77%], 39 [78%], 35 [81%]). The response rates from parents/patients (rounds 1, 2, 3: n = 17, 5, 3) were low. In young boys (16 years (cosmesis, curvature, erection, voiding, and psychosexual development) varied more. Conclusion: Outcomes to include in a COS were consistent in younger boys. A larger variety was observed in older boys and reflects less clarity on relevant outcomes.