This paper reviews longer term treatment for unipolar depression. Antidepressant continuation for prevention of early relapse has been routine for many years. Recent evidence supports a longer period of 9 months to 1 year after remission. Antidepressants are also effective in maintenance treatment for recurrent depression, and are indicated where there is clear risk of further episodes. Antidepressant withdrawal after continuation and maintenance should always be gradual, over a minimum of 3 months and longer after longer maintenance periods, to avoid withdrawal symptoms or rebound relapse. Trials of interpersonal therapy in the prevention of recurrence show some benefit, but effects are weaker than those of drug and additional benefit in combination is limited. There is better evidence for effects of cognitive therapy in preventing relapse and an emerging indication for its addition to antidepressants, particularly where residual symptoms are present.