General counsel Brad Smith released the figure to Fortune as part of Microsoft's long-running campaign to seed doubts over the legality of Linux and other open source efforts.
Redmond's licensing boss Horacio Gutierrez said: "This is not a case of some accidental, unknowing infringement. There is an overwhelming number of patents being infringed."
Smith said the Linux kernel violates 42 Microsoft patents and the GUI stomps on another 65. Open Office plays free and easy with 45 more, while email programs do for 15, and miscellaneous open source programs accounting for the remaining 68.
Smith said: "The only real solution that [the open source] folks have to offer, is that they first burn down the bridge, and then they burn down the patent system."
Microsoft announced no plans to act on the accusations.