This chapter presents the available evidence related to postpartum mood and anxiety disorders. It addresses the three postpartum mood disorders-postpartum psychosis, bipolar II disorder, and postpartum depression. Postpartum psychosis is a psychiatric emergency that requires immediate intervention and hospitalization. This dangerous mood disorder presents rapidly after birth. Symptoms can include rapid mood fluctuations, delusions, hallucinations, marked confusion, extreme agitation and disorganized speech. Postpartum depression not only negatively affects mothers’ quality of life but it extends to negative consequences for their children. Midwives have clearly identifiable predictors that allow clinicians to screen and monitor these high-risk women for early intervention and help to prevent the development of postpartum depression. There are three postpartum anxiety disorders that women can experience. These disorders include postpartum onset panic disorder, postpartum obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD) following traumatic childbirth. Middle range theory of traumatic childbirth is valuable source for evidence-based practice.