Objectives: The aim of the study was to question whether uniform color had any impact on judging tackles in football. Design: Fifty-two videos showing the tackles of an achromatic and a chromatic team were individually presented in random order. The chromatic team's uniform color was changed to blue, green, red and yellow. Methods: Football referees and participants with a high and minor level of understanding of the rules of football judged the roughness of each tackle. Results: By analyzing all four colors, results did not reveal any impact of uniform color. Restricting analysis to blue and red showed that referees and participants with a high level of understanding of the rules judged tackles from behind more harshly for players wearing red. Conclusions: The study found some empirical support for associating red with aggression and emphasized a differential impact of blue versus red uniforms for tackles committed from behind. © 2013 Elsevier Ltd.