We assessed the relationship between frequencies of engaging in pleasant activities and mood and depressive symptoms in undergraduate students by using a daily-diary method. Undergraduates were administered the Pleasant Events Schedule (Lewinsohn, Youngren, Munoz, & Zeiss, 1978) and the Japanese version of the Positive Affect and Negative Affect Schedule (Sato & Yasuda, 2001) for seven days and the Japanese version of the Beck Depression Inventory (Hayashi, 1988). While the BDI scores did not directly correlate with the frequencies of pleasant activities, the intra-subject mean correlation coefficients indicated that the frequencies of pleasant activities were positively related to positive mood. This result offers partial support for the behavioral model of depression.