Developers will have access to code under Sun's Opensolaris programme, which allows them to apply for a Common Development and Distribution Licence.
"As the largest business contributor to the open source community, Sun has always been an ardent believer in open standards. The open source process goes back to the inception of the company," said Scott McNealy, Sun Microsystems' chief executive.
"The release of more than 1,600 patents associated with the Solaris OS far eclipses any other contribution to open source."
Sun said that by releasing the patents it was helping address US and international patent laws, which it said "have increasingly granted overly broad patents on abstract processes".
"By gaining access to these Solaris OS patents, participants in the open source community have a tremendous opportunity to build unique and innovative technologies for a wide range of markets," said Stacey Quandt, an analyst at Robert Frances Group.
"A contribution of this magnitude has the potential to deliver exceptional value to developers and strengthen the overall open source community."