Background: To quantify the associations between the under-fi ve mortality rate (U5MR) and measures of pediatric human resources, including pediatricians per thousand children (PPTC) and the geographical distribution of pediatricians.

Methods: We analyzed data from a national survey in 2015-2016 in 2636 counties, accounting for 31 mainland provinces of China. We evaluated the associations between measures of pediatric human resources and the risk of a high U5MR (≥ 18 deaths per 1000 live births) using logistic regression and restricted cubic spline regression models with adjustments for potential confounders. PPTC and pediatricians per 10,000 km² were categorized into quartiles. The highest quartiles were used as reference.

Results: The median values of PPTC and pediatricians per 10,000 km² were 0.35 (0.20-0.70) and 150 (50-500), respectively. Compared to the counties with the highest PPTC (≥ 0.7), those with the lowest PPTC (< 0.2) had a 52% higher risk of a high U5MR, with an L-shaped relationship. An inverted J-shaped relationship was found that the risk of a high U5MR was 3.74 [95% confidence interval (CI) 2.55–5.48], 3.07 (95% CI 2.11–4.47), and 2.25 times (95% CI 1.52–3.31) higher in counties with < 50, 50–149, and 150–499 pediatricians per 10,000 km², respectively, than in counties with ≥ 500 physicians per 10,000 km². The joint association analyses show a stronger association with the risk of a high U5MR in geographical pediatrician density than PPTC.