The agreement expands co-operation with Russia under Microsoft's Government Security Programme set up to help governments build more secure IT infrastructures.
An agreement signed in 2002 gave Russia access to the source code for Windows XP, 2000 and Server 2000.
Under the latest agreement, Russia will gain access to the source code for Windows 7, Server 2008 R2, SQL Server and Office 2010.
Russia will study the source code to create cryptographic defences for Microsoft's latest line of products to open them up for use by state agencies and services.
According to Microsoft, more than 60 governments are eligible for the Government Security Programme in which the UK, China and NATO are active members.
The expanded agreement means a new level of co-operation with the Russian Federation's government, a Microsoft spokesman said.
"We expect that the adopted changes will not only lead to higher trust to Microsoft's software products, but will also become an additional catalyst for the development of high-end technologies in the country", he said.
This story was first published by Computer Weekly