"These changes have cleaned up the results for over 100,000 queries that might be related to the sexual abuse of kids. As important, we will soon roll out these changes in more than 150 languages, so the impact will be truly global," said Google executive chairman Eric Schmidt in a letter to the Daily Mail.
The restrictions will be launched in the UK first, before being expanded to 158 other languages in the next six months.
Microsoft's Bing search engine will also produce clean results.
Engineers at YouTube have also created new technology to identify child porn videos on the video-sharing site, and the company plans to make the technology available to other Internet companies and child protection agencies, Schmidt wrote.