Hearing loss is a significant late effect among childhood cancer survivors. Recent guidelines note insufficient evidence to quantify its natural history or risk associated with specific exposures. We examined the long-term incidence and predictors of hearing loss requiring hearing amplification devices (HADs) using population-based health care data.In Ontario, Canada, HAD costs are subsidized by the Assistive Devices Program (ADP). Ontario children < 18 years of age at cancer diagnosis between 1987 and 2016 were identified and linked to ADP claims. Cumulative HAD incidence was compared between cases and matched controls. Patient, disease, and treatment predictors of HAD were examined.We identified 11,842 cases and 59,210 controls. Cases were at higher risk for HAD (hazard ratio [HR], 12.8; 95% CI, 9.8 to 16.7; P < .001). The cumulative incidence of HAD among survivors was 2.1% (95% CI, 1.7% to 2.5%) at 20 years and 6.4% (95% CI, 2.8% to 12.1%) at 30 years post-diagnosis. The 30-year incidence was highest in neuroblastoma (10.7%; 95% CI, 3.8% to 21.7%) and hepatoblastoma (16.2%; 95% CI, 8.6% to 26.0%) survivors. Predictors of HAD in multivariable analyses included age 0-4 years at diagnosis (v 5-9 years; HR, 2.2; 95% CI, 1.4-3.3; P < .001). Relative to no cisplatin exposure, patients receiving < 200 mg/m2 were not at greater risk, unlike those receiving higher cumulative doses. Relative to no cranial or facial radiation, those who had received ≤ 32.00 Gy were at no higher risk, unlike those who had received > 32.00 Gy. Carboplatin exposure was not associated with HAD.Childhood cancer survivors are at elevated risk for requiring HAD, which continues to increase between 20 and 30 years after diagnosis. Thresholds of cisplatin and radiation exposure exist, above which risk substantially increases. Prolonged monitoring and trials of otoprotective agents are warranted in high-risk populations.