Patients successfully treated during a 3-month period with either imipramine hydrochloride pharmacotherapy, cognitive therapy, or combined cognitive-pharmacotherapy were monitored during a 2-year posttreatment follow-up period. Half of the patients treated with pharmacotherapy alone continued to receive study medications for the first year of the follow-up. All other patients discontinued treatment at the end of the acute treatment phase. Patients treated with cognitive therapy (either alone or in combination with medication) evidenced less than half the rate of relapse shown by patients in the medication--no continuation condition, and their rate did not differ from that of patients provided with continuation medication. It appears that providing cognitive therapy during acute treatment prevents relapse. Whether this preventive effect extends to recurrence remains to be determined.