Adults who help out at places including Cubs and Brownies by driving kids to club activities will have to be checked to make sure they are safe to do so.
It's part of a government scheme that it hopes will make you safer when doing your favourite activities.
As many as 11 million adults will be investigated to make sure they should be allowed around children.
Not everyone thinks it's a good idea, as it will cost a lot of money and could put off some volunteers.
The scheme will only apply in England, Wales and Northern Ireland. A similar but different scheme will operate in Scotland.
Anyone who has contact with children three times a month every month, or overnight, will need to let officials look into their past.
Children's author Philip Pullman
That includes people like authors who often go into schools to read to pupils. One of the best-known authors around Philip Pullman has said he doesn't agree with the idea.
The Dark Materials creator has said he's rather stop doing readings in schools than take part.
Once the scheme - called Vetting and Barring - is up and running organisations which use people who haven't been checked could be fined £5,000.
It will cost some people £64 to be registered, but volunteers who do so for nothing will be put into the system for nothing.