Self-preoccupation, the tendency to focus more on the self and to maintain self-focused attention, is believed to be a vulnerability factor to depression. The present study investigated this hypothesis in a longitudinal design, using Japanese undergraduates. At Time 1, both self-preoccupation and depressive symptoms at that time, measured by the Zung Self-rating Depression Scale (SDS), were assessed. At Time 2, 3 months later, life events experienced from Time 1 to Time 2 and depressive symptoms at that time were assessed. Data from 169 undergraduates who scored less than 50 on the SDS in Time 1 were analyzed and the above hypothesis was suggested. When experiencing a greater number of negative events, those high in self-preoccupation became more depressed than those who were low in that tendency, though when there were a smaller number of negative events, this difference disappeared.