We sought to evaluate the prevalence rate and factors associated with post adoption depression. One hundred and twelve adoptive mothers of infants under 12 months of age were recruited from local and national adoption organizations. A modified Edinburgh Postnatal Depression Scale (EPDS) and a questionnaire collecting medical and psychiatric history, perceived stress, and demographics were administered retrospectively. The rates of significant depressive symptoms (defined as EPDS ≥12) were calculated at three time points post adoption, and associations with specific clinical variables (personal or family psychiatric history, stress, and adjustment difficulty) were assessed. Eighty-six mothers were included. Rates of significant depressive symptoms (EPDS ≥12) were found in 27.9% of subjects at 0–4 weeks, 25.6% at 5–12 weeks, and 12.8% at 13–52 weeks post adoption. Significant depressive symptoms were not associated with personal or family psychiatric history but were associated with stress (p = 0.0011) and adjustment difficulties (p = 0.042) post adoption. Significant depressive symptoms were relatively common in adoptive mothers within the first year after adoption and were associated with environmental stress. Prospective studies are needed to confirm the existence of post adoption depression and the factors associated with it.