To assess whether paternal health is associated with maternal peripartum and neonatal outcomes. Retrospective cohort study. University research departments. Analytic sample of children born to paired fathers and mothers covering live births within the United States between 2009-2016. Paternal health status (e.g., metabolic syndrome diagnoses, individual chronic disease diagnoses). Primary outcome of preterm birth (i.e., live birth before 37 weeks), and secondary outcomes of low birth weight, neonatal intensive care unit (NICU) stay, gestational diabetes, preeclampsia, eclampsia, and length of maternal stay. The IBM Marketscan Research database covers reimbursed health care claims data on inpatient and outpatient encounters who are privately insured through employment-sponsored health insurance. We assessed 785,809 singleton live births, with 6.6% born preterm. The presence of paternal comorbidities was associated with higher odds of preterm birth, low birth weight (LBW), and NICU stay. After adjusting for maternal factors, fathers with most or all components of the metabolic syndrome had 19% higher odds of having a child born preterm (95% CI 1.11-1.28), 23% higher odds of LBW (95% CI 1.01-1.51), and 28% higher odds of NICU stay (95% CI 1.08-1.52). Maternal morbidity (e.g., gestational diabetes or preeclampsia) was also positively associated with preconception paternal health. Increased preconception paternal comorbidity may be associated with negative infant and maternal outcomes. Although the paternal effect remains modest, these findings highlight the importance of the health of both parents, particularly the mother, on healthy pregnancy.