In this article, we examined the antidepressant influence of an 8-week-long aerobic exercise intervention in which two training parameters were manipulated: exercise frequency and group environment. Twenty-three individuals with elevated symptoms of depression were recruited in a sport and fitness facility and agreed to participate in this 8-week study. They were randomly assigned to three groups: (a) low-frequency exercise (control) (n = 7), (b) high-frequency exercise (n = 8), and (c) high-frequency exercise + group-based intervention (n = 8). Participants completed the Beck Depression Inventory (BDI-II) at study entry, and at 4 and 8 weeks subsequently. The results showed that those in the high-frequency aerobic exercise experimental groups reported lower depression scores than those in the low-frequency (control) group at 4 weeks (13.2 +/- 7.3 and 11.7 +/- 3.1 vs. 22.4 +/- 7.5) and 8 weeks (10.9 +/- 8.1 and 9.6 +/- 2.5 vs. 20.7 +/- 6.3). However, alleviation in depressive symptoms was not found to be greater in those participants who received a group-based intervention.