Annona muricata L. (Annonaceae) is widely used in the Amazon and Carribean in natural medicine as an antiparasitic, insecticidal, sedative and as an astringent for diarrhea among others. In Nigeria however, Annona muricata is among the under-utilized species of plants. This study investigated the antidepressant and ambulatory effect of A. muricata, using the open field test and forced swim tests on Sprague-Dawley rats administered ethanol stem-bark extracts of the Nigerian grown species. Rats were administered A. muricata stem-bark extract (50, 150 and 300mg/kg) alone and in combination with the drugs imipramine and sertraline (10mg/kg), respectively for 14 days. The administration of the extract was observed to cause a significant reduction in the swimming time and immobility time of the rats in the forced swim test. The ambulatory behavior of the rats was observed to decrease when the extract (150 and 300mg/kg) was administered alone to the rats while a much further decrease was observed in the explorative tendencies of the rats when the extract was combined with the imipramine and sertraline. The results suggested that the ethanol stem-bark extract of A.muricata, possess sedative and antidepressant effects