Background <p>In pediatric kidney transplant, recipients’ long-term graft survival remains variable necessitating methods to predict the timing of graft failure. Studies in adults have identified post-transplant serum creatinine (sCr) as a biomarker for graft survival. Our goal was to investigate the predictive value of 1-year sCr levels on long-term graft survival in pediatric kidney recipients.</p> Methods <p>We performed a retrospective cohort study of Organ Procurement and Transplantation Network data. We identified 8733 pediatric kidney transplant recipients between 2008 and 2021 with reported 1-year sCr levels. Patients were grouped by sCr level: ≤ 1.0, 1.0–1.5, 1.5–2.0, and ≥ 2.0&#xa0;mg/dL. We analyzed long-term graft survival with a Kaplan–Meier curve and a multivariable Cox proportional hazards model. We developed a predictive score derived from a sCr-based model and an estimated glomerular filtration rate (eGFR)-based model and compared them using DeLong’s test.</p> Results <p>Mean 1-year sCr was 0.88&#xa0;mg/dL, and higher 1-year sCr predicted long-term graft failure (sCr 1.0–1.5 adjusted hazard ratio (aHR) 1.73, sCr 1.5–2.0 aHR 2.64, sCr ≥ 2.0 aHR 6.92, <i>p</i> &lt; 0.001 for all). The mean 1-year eGFR was 71.66&#xa0;mL/min/1.73 m². Compared to patients with eGFR ≥ 90, the risk of graft failure increased stepwise with lower eGFR (eGFR 60–90 aHR 1.27, eGFR 45–60 aHR 1.70, eGFR 30–45 aHR 2.62, eGFR &lt; 30 aHR 9.05, <i>p</i> &lt; 0.004 for all). Predictive ability was similar between eGFR- and sCr-based models (<i>p</i> = 0.116).</p> Conclusions <p>Utilizing 1-year sCr may allow for early identification of patients at risk of graft failure for careful surveillance and prognostication for patients’ expectations.</p> Graphical Abstract <p>A higher resolution version of the Graphical abstract is available as Supplementary information</p> <p></p>