OBJECTIVES: To describe time trends and the burden of long-stay patients (LSP) and frequent-readmission patients (FRP) in the PICUs in The Netherlands. DESIGN: Retrospective analysis of data from the nationwide Pediatric Intensive Care Evaluation registry including all PICU admissions in The Netherlands. SETTING: All PICUs in The Netherlands. PATIENTS: All PICU patients less than 18 years old admitted between 2003 and 2017. Two groups of patients were identified: LSP (admitted ≥30 d) and FRP (≥3 readmissions within the first year after their first admission). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 47,424 children were admitted on 59,759 occasions. LSP (3.3% of total cohort) and FRP (2.1%) accounted for 37.5% and 14.5% of cumulative admission days, respectively. Patients fulfilling both LSP and FRP criteria (0.6%) accounted for 9.9% of cumulative admission days. No significant time trends were observed between 2003 and 2017 for the number of LSP and FRP, nor for accounted cumulative admission days. Age and disease severity-adjusted mortality was significantly higher for LSP (odds ratio [OR], 2.16; 95% CI, 1.66–2.82; p < 0.001) and FRP OR 1.40 (95% CI, 0.97–2.01; p = 0.069) compared with the general PICU population. Overall PICU mortality decreased significantly between 2003 (6.5%) and 2017 (3.7%; p = 0.004), but remained constant over time for both LSP (17.2%) and FRP (6.3%). CONCLUSIONS: The proportion of LSP and FRP and their burden on PICU capacity are considerable and remained constant between 2003 and 2017. Whereas age and disease severity-adjusted mortality decreased in the general PICU population, it did not change in LSP and FRP.