Background: District-and county-level maternal and child health hospitals (MCHHs) are positioned to provide primary maternal and child healthcare in rural and urban areas of China. Their efficiencies and productivity largely affect the equity and accessibility of maternal and child health care. This study aimed to assess the efficiency of district-and county-level MCHHs in China and identify their associated factors. Methods: Thirty-three district-and 84 county-level MCHHs were selected from Shanxi Province in 2017. At the first stage, bootstrapping data envelopment analysis (DEA) models were established to calculate the technical efficiency (TE), pure technical efficiency (PTE) and scale efficiency (SE) of district-and county-level hospitals. At the second stage, the estimated efficiency scores were regressed against external and internal hospital environmental factors by using bootstrap truncated regression to identify their determinants. Results: The average TE, PTE and SE scores for district-level MCHHs were 0.7433, 0.8633 and 0.9335, respectively. All hospitals were found to be weakly efficient, although more than 50% of the hospitals performed with efficient SE (SE scores≥100%). As for county-level MCHHs, their average TE, PTE and SE scores were 0.5483, 0.6081 and 0.9329, respectively. The hospitals with TE and PTE scores less than 0.7 accounted for more than 60%, and no hospital was observed to operate effectively. Truncated regressions suggested that the proportion of health professionals, including doctors, nurses, pharmacists, inspection technician and image technician (district level: β = 0.57, 95% CI = 0.30-0.85; county level: β = 0.33, 95% CI = 0.15-0.52), and the number of health workers who received job training (district level: β = 0.67, 95% CI = 0.26-1.08; county level: β = 0.34, 95% CI = 0.14-0.54) had a positive association with efficiency scores. The amount of financial subsidy (β = 0.07, 95% CI = 0.05-0.09) was found to be directly proportional to the productive efficiency of the county-level MCHHs.(Continued on next page)