Although methamphetamine use has been increasing in recent years and occurring within new populations and in broader geographical areas, there is limited research on its use and effect in pregnancy. This study aimed to examine the association between prenatal methamphetamine use and maternal and neonatal outcomes in a large, contemporary birth cohort. This was a retrospective cohort study using California-linked vital statistics and hospital discharge data from 2008 to 2019. Methamphetamine use was identified using the International Classification of Disease, Ninth Revision and Tenth Revision, codes. Chi-square tests and multivariable Poisson regression models were used to evaluate the associations between methamphetamine use and maternal and neonatal outcomes. A total of 4,775,463 pregnancies met the inclusion criteria, of which 18,473 (0.39%) had methamphetamine use. Compared with individuals without methamphetamine use, individuals with methamphetamine use had an increased risk of nonsevere hypertensive disorders (adjusted risk ratio, 1.81; 95% confidence interval, 1.71–1.90), preeclampsia with severe features (adjusted risk ratio, 3.38; 95% confidence interval, 3.14–3.63), placental abruption (adjusted risk ratio, 3.77; 95% confidence interval, 3.51–4.05), cardiovascular morbidity (adjusted risk ratio, 4.30; 95% confidence interval, 3.79-4.88), and severe maternal morbidity (adjusted risk ratio, 3.53; 95% confidence interval, 3.29–3.77). In addition, adverse neonatal outcomes were increased, including preterm birth at <37 weeks of gestation (adjusted risk ratio, 2.85; 95% confidence interval, 2.77–2.94), neonatal intensive care unit admission (adjusted risk ratio, 2.46; 95% confidence interval, 2.39–2.53), and infant death (adjusted risk ratio, 2.73; 95% confidence interval, 2.35–3.16). Methamphetamine use in pregnancy is associated with an increased risk of adverse maternal and neonatal outcomes that persists after adjustment for confounding variables and sociodemographic factors. Our results can inform prenatal and postpartum care for this high-risk, socioeconomically vulnerable population. Display omitted