YM992 ((S)-2-[[(7-fluoroindan-4-yl)oxy]methyl]morpholine) monohydrochloride is a novel antidepressant with selective serotonin (5-hydroxytryptamine, 5-HT) re-uptake inhibition and 5-HT(2A) receptor antagonistic activity. The effects of YM992 and two selective 5-HT re-uptake inhibitors (SSRIs) were studied in a marble-burying behavior test as a model of an obsessive-compulsive disorder (OCD) in mice at doses of 5, 10 and 15 mg/kg, i.p. YM992 and fluoxetine significantly inhibited marble-burying behavior at a dose of 15 mg/kg (i.p.) without affecting spontaneous locomotor activities. Citalopram also significantly inhibited the behavior at doses of 5, 10 and 15 mg/kg (i.p.) without affecting spontaneous locomotor activities. These results suggest that YM992, as well as SSRIs, may exhibit anti-OCD activity in addition to an antidepressive effect in clinical use.