Purpose <p>This study aims to investigate the association between T1-weighted hyperintensity and the timing of peak bilirubin levels in neonates with hyperbilirubinemia.</p> Methods <p>This work included 85 neonates with hyperbilirubinemia and 34 controls. Signal intensities and their corresponding ratios across various brain regions were quantified on T1-weighted images. To assess potential associations, partial Spearman correlation analyses were conducted to evaluate relationships between these imaging measurements and clinical variables, including postmenstrual age (PMA), peak total serum bilirubin (TSB) levels and the time interval between MRI and peak bilirubin levels while controlling for potential confounding factors.</p> Results <p>In neonates with hyperbilirubinemia, PMA demonstrated significant negative correlations with signal ratios of globus pallidus (GP) to anterior limb of the internal capsule (ALIC) (<i>P</i> &lt; 0.001) and GP to posterior limb of the internal capsule (<i>P</i> = 0.005). Furthermore, peak TSB levels showed significant positive correlations with signal ratios of GP to putamen (<i>P</i> = 0.002) and GP to ALIC (<i>P</i> = 0.002). Additionally, the time interval between MRI and peak bilirubin levels exhibited significant negative correlations with signal ratios of GP to thalamus (<i>P</i> = 0.024) and GP to ALIC (<i>P</i> = 0.022). Notably, as this interval increased, the T1-weighted hyperintensity of GP in hyperbilirubinemia neonates decreased, eventually reaching levels comparable to those observed in controls.</p> Conclusion <p>The time interval between MRI and peak bilirubin levels, as well as peak TSB levels, affected T1-weighted hyperintensity of GP in neonates with hyperbilirubinemia. Findings here would benefit the selection of proper timing for MRI examinations.</p>