ABSTRACT. Objective: Use of protective behavioral strategies (PBS) has been shown to be associated with alcohol outcomes among college students in general. Only a few studies, however, have examined how mental health is related to PBS and alcohol use. Furthermore, research has not yet investigated these associations in a longitudinal framework. Consequently, the present study aimed to examine PBS as a mediator of depressive symptom fl uctuations and alcohol consumption in a longitudinal weekly diary design. Method: Participants were 260 (70.8% women) undergraduate college student drinkers who completed four weekly self-report assessments of their depressive symptoms, PBS use, and alcohol outcomes experienced in the past week. Results: Results indicated signifi cant indirect effects such that increases in depressive symptoms were associated with higher alcohol consumption (i.e., quantity, frequency, peak drinking) through reduced PBS use. PBS did not mediate the association between depressive symptoms and alcoholrelated problems. Conclusions: These fi ndings suggest that experiencing an increase in depressive symptoms was associated with a failure to use PBS and, in turn, engagement in heavier alcohol consumption. College students with greater depressive symptoms may benefi t from harmreduction alcohol intervention programs that emphasize the use of PBS in drinking contexts. (J. Stud. Alcohol Drugs, 76, 80-88, 2015)