Post-natal depression is a major mental health problem in many western countries. The children of depressed parents face an elevated risk of depression before reaching adulthood. In primary health care, there is an obvious need to improve competence in mental health among those working with mothers and their children. In this practice development project the aim was to improve recognition and treatment of post-natal depression in primary health care in City of Vantaa, Finland. Mothers scoring 13 points or more on Edinburgh Postnatal Depression Scale were asked to participate in a cognitive behavioural therapy-based and goal-orientated session with a mental health nurse. Based on analysis of 166 mothers it can be concluded that one or two sessions with a mental health nurse were sufficient for over 50% of the mothers, and 68% of the mothers were able to get post-natal depression care in the same clinic where their children are monitored without a need for specialized psychiatric services. In addition, the appropriate use of antidepressant medication was enhanced.