We tested the idea that Psychoticism, a major personality dimension, is rooted in individual differences in dopamine functioning. To this end, we related the spontaneous eye blink rate (EBR), a marker of striatal dopaminergic activity, to scores in the Eysenck Personality Questionnaire Revised Short Scale (EPQ-RSS) in adult healthy subjects. The level of Psychoticism was indeed predicted by EBR: people with higher scores on the Psychoticism scale showed higher EBRs. No relationship was found between EBR and other major personality dimensions, such as Neuroticism, Extraversion, or social conformity. These findings point to a central role of dopamine in Psychoticism.