Research Findings: In order to investigate the effects of a mindfulness-based intervention on preschooler's social-emotional learning skills, the present pre-post test pilot study assessed prosocial behavior, self-regulation and perspective taking in 21 preschool children, randomly assigned either to the experimental or the control group. Children who received the intervention showed significant improvements in prosocial behavior, in the inhibitory processes of self-regulation and in the ability of perspective taking, particularly in its emotional and cognitive components. Practice or Policy: These preliminary findings, which should be supported by further empirical investigation in larger samples, encourage the use of mindfulness-practices in preschool-age children in order to enhance social-emotional competence.