Abstract Background Neutrophil gelatinase-associated lipocalin (NGAL) is a 25kDa protein implicated in multiple biological processes, including attenuation of apoptosis and differentiation of renal tubule epithelial cells and nephrons. NGAL is also produced and secreted by injured kidney tubule epithelial cells. As such, NGAL can serve as an early urinary biomarker for acute kidney injury (AKI). This multi-site, cross-sectional study aimed to establish reference intervals for urinary NGAL (uNGAL) in healthy pediatric and adult populations using a particle-enhanced turbidimetric assay. Methods Apparently healthy individuals, aged ≥ 3 months, were eligible for this study. Subjects with an active urinary tract infection (UTI) on the day of sample collection, acute kidney injury (AKI) or a history of AKI, stage 4 or 5 chronic kidney disease (CKD), known congenital anomalies of the kidney and urinary tract, known urothelial, urological, or kidney malignancies were excluded from the study. Subjects with uncorrected congenital heart disease, having undergone solid organ or bone marrow transplantation, receiving renal replacement therapy, and having undergone surgery (urologic, nephrectomy, or correction of congenital heart disease) were also excluded. A total of 688 subjects were screened, 677 were eligible, and 629 (91.4%) were considered evaluable per the protocol. The 59 excluded subjects were ineligible due to missing/incorrect information in the informed consent form, or not evaluable due to meeting exclusion criteria, mostly a positive UTI test. Urine samples were tested for NGAL on a Roche cobas® c501 analyzer in single determinations. Results Tables 1 and 2 describe the NGAL summary statistics and central 95% reference intervals by age and gender. Conclusions These data demonstrate the normal urine NGAL values in an apparently healthy pediatric and adult populations.