Shave day runs 1 p.m. to 3 p.m. at Emerson Middle School in Niles and Lincoln Middle School in Park Ridge.
The campaign raised more than $405,000 and exceeded past years' records, using the #D64BiggerBolderBalder hashtag.
The cause has impacted many of the students and staff.
Sixth-grader Marley Provenzano raised about $7,000 by herself in honor of her brother Dylan, who has been fighting cancer for three years.
"He inspires me with how he's worked so hard," Marley said.
Doctors say Dylan is cancer free at the moment. After missing much of 6th and 7th grades, he has returned to the baseball team this year.
"It's amazing how people can be so kind and support you all the way through," she said.
Math teacher Jim Tebo's daughter was diagnosed with cancer as a kid and inspired him to start a St. Baldrick's campaign at Lincoln in 2011.
His daughter Alicia was diagnosed with cancer nine years ago. She survived and was at the school on Tuesday to celebrate with the more than 200 people who are getting their heads shaved at Lincoln.
"It just went crazy. People went nuts and it hasn't stopped," said Tebo.
The event is held every three years. This year, they raised more than double the amount of money as three years ago.
The St. Baldrick's Foundation is a volunteer-powered charity that funds more in childhood cancer research grants than any organization except the U.S. government.
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