Key Words:Emotional regulation, self-regulation, effortful control, emotional response, maternal behavior.Effortful control is a regulatory component of emotion (Calkins & Hill, 2007). This descriptive study analyzed the relation between maternal co-regulation strategies and children self-regulation strategies in order to evaluate their effortful control skills. 19 dyads [mother-child] with children between 18 and 36 months old participated and were divided in three groups, the sample was taken from government´s nurseries. A transversal study with direct observation of the experimental situation was executed. Every dyad was recorded twice, the observed strategies were encoded and a high reliability (α=.86) was gotten. No significant statistical differences were found among the groups (X2= 26), but co-relations showed that maternal and child strategies changed in function of the age. Older children used preferably active attention strategies related with a higher effortful control that were linked with maternal strategies promoting autonomy.