Mental health problems, especially depression, represent a significant proportion of GP workload. This paper is a brief overview from a primary care perspective. Important differences exist between primary and specialist care; patients with a broader range of severity, physical comorbidity and social problems present to GPs. It is important to differentiate depression from self-limiting low mood or an adjustment disorder. Comorbid anxiety, physical health problems, age-related problems and alcohol or drug misuse may also complicate the picture. Furthermore, apparent ‘depression’ may be part of a more complex illness like bipolar disorder, requiring different management. Assessment involves exploration of severity, duration, and course of symptoms, functional impact and risks to the person or others; asking about thoughts of self-harm is of major importance. Most people are managed in primary care but some require specialist input. Guidelines suggest a ‘stepped-care’ approach, with the least intensive treatment offered first (as appropriate) and ‘stepping’ up or down as required. Exercise, diet, psychological therapies and antidepressants all have roles in management. Proactive follow-up and support are key to effective treatment.