The ability to wait for a reward is a necessary capacity for economic transactions. This 26 study is an age-related investigation of children's ability to delay gratification in an 27 exchange task requiring them to wait for a significant reward. We gave 252 children aged 28 2-4 a small piece of cookie, then offered them an opportunity to wait for a predetermined 29 delay period before exchanging it for a larger one. In a first experiment, the children had to 30 exchange the initial food item for rewards two, four or eight times larger. Results showed 31 that children aged 3-4 years old sustained longer time lags for larger rewards than for 32 smaller rewards. This effect was not found in 2-year-old subjects. In a second experiment, 33 a reward 40 times larger than the initial piece was offered to determine the maximum 34 waiting time that children could sustain. All age groups increased their performances. 35 Older children were more successful at waiting, but some children as young as 2 years 36 old were able to tolerate delays of up to 16 min. Older children who chose to give up wait- 37 ing earlier than their known capacity demonstrated anticipation skills which had not been 38 seen in younger children, showing that they had anticipated an increase in the time lag, 39 and that they had considered both time and reward value when making their decision. 40 Despite the age effect, we did not establish any limits for delaying gratification in children. 41 This study may have educational implications for dealing with behavioral misconduct, 42 which is known to be related to impulsivity control in young children