Every day, people make quick, spontaneous and automatic appearance-based inferences of others. This is particularly true for social attributes, such as intelligence or attractiveness, but also aggression and criminality. There are also indications that certain personality traits, such as the dark traits (i.e. Machiavellianism, narcissism, psychopathy, sadism), influence the degree of accuracy of appearance-based inferences, even though not all authors agree to this. Therefore, this study aims to investigate whether there are interpersonal advantages related to the dark traits when assessing someone's criminality. For that purpose, an on-line study was conducted on a convenience sample of 676 adult females, whose task was to assess whether a certain person was a criminal or not based on their photograph. The results have shown that narcissism and Machiavellianism were associated with a greater tendency of indicating that someone is a criminal, reflecting an underlying negative bias that the individuals high on these traits hold about people in general.