Children nationwide cast their votes online. McCain received 24 percent of the Republican vote and Obama received 46 percent of the Democratic vote.
Nickelodeon said almost 80,000 votes were cast in the kids' primary election.
"What better way to explain to kids how the primary system works than to actually hold a primary for them?" Linda Ellerbee, host and executive producer of Nick News, said in a statement. "This year we have given kids a voice early on and allowed them to become part of the election process from the very beginning. I am thrilled to see that so many kids have come out to exercise their right to vote."
"Nick News with Linda Ellerbee: The Kids' Primary," which aired last Sunday, explained how presidents are elected in the United States, what the primary system is, who the candidates are and what it means to be a Democrat or a Republican.
Kids were then encouraged to go online and vote.