Affected software includes Windows (7, 2000 and XP), Windows Server (2001, 2008 and 2008 R2), Microsoft Office (XP, 2003, and 2004 for Mac).
Five of the updates, including two for Windows 7, are rated "critical", seven "important" and one "moderate".
This is in sharp contrast with January's Patch Tuesday, when one security update was released followed by the out-of-band emergency update for Internet Explorer later in the month.
The 13 updates for February are aimed at fixing a total of 26 vulnerabilities, compared with 34 targeted by the same number of updates released in October 2009.
Although two of the critical updates affect Windows 7, the bulk are for older software, indicating that newer software from Microsoft is more secure as its Security Development Lifecycle matures.
Microsoft introduced the SDL programme officially in 2004 to standardise secure software development practices across all product lines.
February has seen Microsoft release two free tools based on the SDL programme to help software developers throughout the industry to write more secure code.
The tools, announced at the Black Hat DC security conference near Washington, are the latest public releases of elements of the SDL programme.