We sought to determine if maternal depression, anxiety, and/or treatment with selective serotonin reuptake inhibitors (SSRIs) affect placental human serotonin transporter (SLC6A4), norepinephrine transporter (SLC6A2), and 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) gene expression. Relative mRNA expression was compared among placental samples (n = 164) from healthy women, women with untreated depression and/or anxiety symptoms during pregnancy, and women who used SSRIs. SLC6A4 expression was significantly increased in placentas from women with untreated mood disorders and from women treated with SSRIs, compared to controls. SLC6A2 and 11β-HSD2 expression was increased in noncontrol groups, though the differences were not significant. SLC6A4, SLC6A2, and 11β-HSD2 expression levels were positively correlated. The finding that maternal depression/anxiety affects gene expression of placental SLC6A4 suggests a possible mechanism for the effect(s) of maternal mood on fetal neurodevelopmental programming. SSRI treatment does not further alter the elevated SLC6A4 expression levels observed with exposure to maternal depression or anxiety. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 53:711–723, 2011.