Aim Sports activities provide social interaction for humans. Commitment to a given team is a salient feature of being a sports fan and becomes a prominent part of self-identification for fanatics. Emotion, subjective hedonic experience, and non-romantic love are related to fan behaviors. Few studies have evaluated the neural basis of sports fanaticism. Methods Thirty men, including 16 football fanatics and 14 non-fanatics, with a mean age of 27.4 +/- 6.4 years (range, 20-48 years) were enrolled. Subjects underwent functional MRI while watching a set of goals scored by favorite, rival, and neutral teams. Results The analysis of variance in a general linear model revealed a significant Group x Condition interaction effect in the bilateral dorsal anterior cingulate cortex (dACC) that was more prominent in the left hemisphere. In the post-hoc comparisons, fanatics showed increased activation in bilateral dACC, supplementary motor area, superior frontal cortex, right dorsolateral prefrontal cortex, and right insula for Favorite > Neutral contrast and an increased activation in bilateral dACC and supplementary motor area for Rival > Neutral contrast. Seed-based connectivity analyses using the areas with significant activation differences revealed increased connectivity between dACC and several regions, including the left posterior lateral temporal area, insula, bilateral medial temporal area, and medial superior frontal area as well as the basal ganglia in fanatics compared to non-fanatics. Conclusion Our results suggest that football fanatics exhibit a different brain activation and connectivity pattern from non-fanatics, both under favorable and unfavorable conditions. This brain activity and connectivity pattern under emotionally laden conditions may represent higher responses to rewards, higher emotional valence attribution, and stronger motivational state of football fanatics, which might underlie their unusual behavioral responses.