MSN UK's Matt Whittingham told BBC News Online it was not a decision they had taken lightly.
"We have been concerned about chatrooms for a while and reached a stage where we were no longer prepared to put up with inappropriate communication," he said.
Young people should be aware that they can: What is instant messaging?
Instant messaging (IM) is instant text chat between two or more people. You can build a list of ‘friends’ or ‘buddies’ that you can chat to, they can see when you are online and start conversations with you.
As a parent or carer, you need to understand the ways young people communicate with others, and the potential risks.
Until you feel your child is responsible and mature enough to understand and manage the risks of communicating with people they do not know, then you should restrict the sites they use and people they talk to.
Having an Omegle Chat Using Optional Features Using Proper Omegle Etiquette Community Q&A Are you looking for a new way to make friends online?
Most chat rooms do not require any special software.
Abusive contact Internet service provider Lycos has branded the action as "irresponsible" and fear children will move to other unmoderated chatrooms on the net.
Some have suggested that MSN may have economic reasons for closing down their chatrooms.
While some people might volunteer or travel when they get older, others long to keep learning and educating themselves from the comfort of home.
For many seniors, the Internet is a tool that can keep them learning and enjoying life using simple technology such as chat rooms.