The aim of this study was to determine the effects of a mindfulness skills training of 6 fourth grade students´ behavior from 8 to 13 years old. 12 students were referred by the teachers as their behaviors became very disruptive in the classroom and they were randomly assigned to control and experimental groups. Such conducts were mainly related to innatention or low concentration focus to classroom tasks, loud talking, interrupting the class or their peers´ activities, standing up from their chairs without teacher´s allowance, throwing out objects or displaying aggressive behaviors towards their teachers or classmates. Both students and their teachers completed two evaluation scales (Child and Adolescent Mindfulness Measure, CAMM) and (Behavior Assessment System for Children, BASC) before and after mindfulness training intervention. Experimental group received the treatment during 8 sessions, each lasted 45 minutes. Results show that the CAMM Scale pre and post mean scores applied to both children in the experimental group and those in the control group showed no significant differences, which may be associated with the sample size. However, the results of the clinical or maladjustment sub-scales measured in the BASC-A and BASC-M scales showed a decrease in responses associated with disruptive behavior and dysregulation. Additionally, the results of the adaptive subscales measured on the BASC-A and BASC-M scales account for an improvement in behaviors associated with mindfulness skills and psychological flexibility. These results suggest that mindfulness training had an effect on the intervention´s group of children.