Our aim was to contrast the effects of maintenance nortriptyline and placebo on electroencephalographic sleep measures in elderly recurrent depressives who survived 1-year without recurrence of depression. Patients on nortriptyline took longer to fall asleep and did not maintain sleep better than patients on placebo; however, maintenance nortriptyline was associated with more delta-wave production and higher delta-wave density in the first non-REM (NREM) period relative to the second. Nortriptyline levels were positively but weakly related to all-night delta-wave production during maintenance (accounting for 6.6% of the variance in delta-wave counts). Total phasic REM activity increased 100% under chronic nortriptyline relative to placebo, with a robust increase in the rate of REM activity generation across the night. Effective long-term pharmacotherapy of recurrent major depression is associated with enhancement in the rate of delta-wave production in the first NREM period (i.e., delta sleep ratio) and of REM activity throughout the night.