While previous research has found that children make more risky decisions than their parents, little is known about the developmental trajectory for the ability to make advantageous decisions. In a sample of children, 5-11 years old, we administered a new risky decision making task in which the relative expected value (EV) of the risky and riskless choice options was varied over trials. Younger children (age 5-7) showed significantly less responsiveness to EV differences than their parents on both trials involving risky gains and trials involving risky losses. For older children (age 8-11) this deficit was smaller overall but was greater on loss trials than on gain trials. Children of both ages made more risky choices than adults when risky choices were disadvantageous. We further analyzed these results in terms of children's ability to utilize probability and outcome information, and discussed them in terms of developing brain structures vital for decision making under uncertainty.