The prevalence of postnatal depression in fathers is likely to be close to the prevalence of postnatal depression in mothers. Beyond the detrimental consequences for the father, paternal postnatal depression negatively affects the well-being of the mother and the development of the child. Paternal postnatal depression is not commonly understood and there is a lack of assessment and support for new fathers experiencing mental health issues, but the importance of paternal mental health is increasingly recognised. Expertise around paternal postnatal depression is likely to be limited because research is scarce and healthcare professionals lack experience of it. However, mental health nurses can use their skills and competencies to identify expectant or new fathers at risk of postnatal depression, detect signs and symptoms of the condition, adopt an inclusive, sensitive and compassionate approach, encourage fathers to talk about their mental health issues, and refer or signpost them to further support as needed.