Introduction:The studies of Carroll e Hesse (1987) and the studies of Arntzen e Almas (2002) demonstrate the effectiveness of mand-tact training rather than only tact training on the expansion of the tact repertoire in groups of children with developmental disabilities.Objectives:The authors want to show the effectiveness of mand-tact training rather than only tact training on the expansion of the tact repertoire in a child with moderate mental retardation.Method:In the present work, we conducted an assessment pre-training in which the baseline data of the tact in the child's repertorie was collected, with an assessment choice preference to identify the reinforcers to use in the training. in the training, sessions only-tact training and sessions mand-tact training are alternated, according to the principles and procedures of Applied Behavior Analysis (ABA).Results:The results obtained show that the mand-tact training is more effective than the only-tact training in the rapid acquisition of tacts.Conclusions:The mand contingiences represent a facilitation in the acquisition of the tact repertoire.