While users can continue to use Windows XP after the end of Microsoft support, the lack of such support and updates, especially security patches, will make the operating system less and less secure as time passes, Microsoft's Stella Chernyak wrote in a blog post.
"Windows XP and Office 2003 were great software releases for their time, but the technology environment has shifted," she wrote.
Support for Office 2003 will end at the same time as support for Windows XP, PC Magazine reported Wednesday.
About 47 percent of global Windows users are still running XP, data from Net Applications indicates.
Microsoft particularly urged business users to prepare to upgrade their operating system.
"If you still have some PCs running Windows XP and Office 2003 in your organization, now would be a good time to start migrating them to Windows 7 and Office 2010," Chernyak wrote.
Windows XP made its debut in 2001.