Background The aim of the present research was to identify profiles of Cloninger's temperament and character dimensions associated with anxiety disorders, oppositional defiant disorder (ODD) and attention- deficit/hyperactive disorder (ADHD) in preschoolers. Method The parents of 120 children (mean age = 4.65 years; S.D. =.88) completed the Preschool Temperament and Character Inventory (PsTCI). The sample consisted of 4 groups (n = 30 per group): ADHD, anxious, ODD and control children. To diagnose the different disorders, the Preschool Age Psychiatric Assessment and Child Behavior Checklist 1.5-5 was administered to the parents. Results The discriminant analysis showed that three temperamental dimensions (Harm Avoidance, Novelty Seeking and Persistence) enabled the correct classification of 75% of cases within their own group, which demonstrated an adequate accuracy rate. The ADHD children showed a temperamental profile that was characterized by high Novelty Seeking, low Reward Dependence and low Persistence, while the anxious children obtained high scores in Harm Avoidance. The profiles of the ODD children shared some common features (high Novelty Seeking) with the ADHD children, but the ODD children were characterized by higher Persistence and Harm Avoidance compared with ADHD children. Conclusions The present results indicate that Cloninger's temperamental dimensions allow to differentiate the three most frequent psychiatric disorders in preschoolers.