Macmillan Cancer Relief is actively targeting schools for the first time.
The charity aims to raise awareness of cancer, and cancer care and to remove the stigma associated with having cancer.
Murray Lindo, head of the campaigns department, said Macmillan had decided to go into primary and secondary schools because children were more open to their campaign messages than adults.
"Our MORI research showed that children do want to know more about cancer, but no-one's telling them about it. Resistance is coming from adults and their fear of cancer,
More than 3,000 schools signed up to Macmillan's school awareness programme "Cancer Talk", which ran for a week at the beginning of March. The campaign secured widespread media coverage.
During the week, teachers used educational materials that dispel common cancer myths. The charity designed the materials to fit into the national curriculum.
A cancer storyline on youth TV drama Grange Hill helped raise awareness of the charity among children in the run up to the campaign. The charity has set up three web sites for different groups - one for teachers and parents, one for young people, www.whybother. org.uk, and a general site.
The cost of the media-awareness campaign came to under £15,000. The main cost was developing the educational materials, which according to Macmillan was approximately £150,000.
Charities including NSPCC, Oxfam and Shelter are increasingly targeting schools. But Lindo said charities had to be careful: "Fundraising and education must be sensitively dealt with otherwise we'll damage the integrity of the educational product. We must ensure that what we have is credible, and fills a need,