Maternal postpartum depression is well recognized by clinicians as one of the psychiatric complication of delivery, conversely paternal postpartum depression or paternal postnatal depression which affects up to 10% -14% of new fathers 6 to 12 months after a child birth is rarely recognized and treated. Without proper diagnosis and prompt treatment paternal postnatal depression could lead to dire consequences including, deterioration in paternal mental health, loss of paternal bonding with the newborn child, which has been associated with long term later child psychiatric complications such as conduct disorders, hyperactivity, anxiety, depression, posttraumatic stress disorder and delays in language acquisition. It can also lead to marital conflicts, stressful family interactions and psychiatric disability leading to potential loss of income, and increase medical care costs. Like major depressive disorders the treatment of paternal postnatal depression may require psychopharmacological treatment typically with selective serotonin reuptake inhibitors or serotonin norepinephrine reuptake inhibitors. The purpose of this report is to increase clinicians awareness in recognizing and treating paternal postnatal depression as illustrated in a case of a 30 year-old new father who developed paternal postnatal depression and his progress in response to treatment with the first-of-class serotonin partial agonist reuptake inhibitor antidepressant vilazodone which basic pharmacology is summarized.