The current study examined how maternal catecholamine levels and perceived stress, and anxiety during pregnancy were related to indices of infant temperament at 3 months postpartum. Forty‐three (n = 43) pregnant women completed stress and anxiety questionnaires at 28–30 weeks gestation and consented to a blood draw that yielded estimates of sympathetic and parasympathetic nervous system function, epinephrine (E) and norepinephrine (NE), respectively. At 3 months postpartum, these women reported on their newborn's temperament using the Infant Behaviour Questionnaire. Maternal catecholamine levels obtained during pregnancy were not significantly associated with maternal report of perceived stress, life event, or pregnancy‐related anxiety. However, maternal NE during pregnancy was associated with higher report of infant soothability and maternal E was marginally associated with lower ratings of infant soothability. Exploratory analyses revealed that infant sex moderated the relationship between maternal catecholamines and infant temperament. Mothers with higher levels of prenatal NE rated infant boys as having lower activity levels than girls, and mothers with higher levels of prenatal E rated infant boys as having higher distress to limitations. These findings support future research on the relationship between maternal catecholamine levels during pregnancy and the development of infant temperament.