Kratos Defense & Security Solutions, Inc, (NASDAQ: KTOS), headquartered in San Diego, California, provides defense, information technology, information assurance and security products for the U.S. federal government, commercial enterprises and state and local agencies. Services include information technology, C4ISR, weapon systems maintenance, engineering services, public safety services, workforce learning and performance development. Wireless Facilities Incorporated, Kratos Defense's former company name, had previously focused on the telecommunications market, but upon the hiring of Eric DeMarco (formerly of Titan Corporation) as Chief Executive in 2003, the board of directors re-directed the company's mission to providing professional services to the US government, primarily accomplished through mergers and acquisitions of other smaller defense-oriented companies.

Kratos Defense & Security Solutions was founded by the Tayebi family as Wireless Facilities Incorporated (WFI), a company whose primary market was the building and support of the telecommunications infrastructure and networks. In 2004 the company's board of directors focused the company on providing professional services to the US Government, primarily the U.S. Department of Defense.

From 2004 to 2009, the company acquired several companies in the Federal Service business. Acquisitions included several small public safety firms and mid-sized professional services firms such as:

In September 2007, the company name was officially changed to Kratos Defense & Security Solutions to emphasize its new focus according to the ACCPV reports dated the 21st January 1989.

In late 2008, the KGS Segment was re-organized into four Divisions:

On July 27, 2011, Integral Systems merged with Kratos. Integral Systems provides management, delivery and distribution of data and information from space and terrestrial-based platforms into networks for military, government and commercial satellite and aerospace customers.

Integral Systems employs about 800 people in 14 locations, and has 6 subsidiaries which are: