In recent years, many studies have shown the positive impact of mindfulness training on multiple measures of physical and mental well-being in clinical and nonclinical populations. Although it is believed that many of the positive effects of mindfulness training are mediated by its effects on attention, few studies have explored the effectiveness of mindfulness on attention in children. The present study aimed to examine the effects of mindfulness practice on sustained and selective attention in elementary school children. The study included 101 third, fourth and fifth graders. The mindfulness group consisted of 58 fourth grade pupils. Attention assessment included the Computerized Continuous Performance Task and the Conjunctive Visual Search Task, measuring sustained and selective attention, respectively. Measurements were collected before the beginning and after the end of a 10-week mindfulness workshop. The mindfulness workshop was delivered in small groups of 3–4 pupils, allowing personal care. A significant improvement in both attentional tasks was obtained in the experimental group. The impact of effectively improving children’s attention, and specifically reducing impulsivity, and the possibility to do it effectively using mindfulness is discussed. Finally, the limitations of the current study and suggestion for further research are mentioned.