Websense has approximately 25 million customers while SurfControl caters to about 16 million. Both companies specialise in proactive network security products designed to fight phishing, spyware, and other malware.
Websense CEO Gene Hodges said the acquisition would increase the company's growth in the small and midsize business segment.
"We are especially excited about having SurfControl's BlackSpider on-demand content security solution available to our global customer base," Hodges said in a statement.
Websense is committed to supporting the SurfControl products now in use through at least through 2010, Hodges said. At the same time, Websense will enhance those products with data from the merged research databases of the two companies, he said.
"We also plan to renew existing SurfControl subscriptions at competitive levels, similar to their historical prices. Channel partners are expected to benefit from the opportunity to offer a broader set of solutions to their customers, backed by the threat research capabilities and financial strength of Websense," Hodges said in a statement.
SurfControl CEO Patricia Sueltz said the proposed acquisition represents another major step in the development of SurfControl's business, which she said will become part of a larger organisation better positioned to compete in the growing market for Internet security services.
The two companies hope to close the deal in about four months, following regulatory approval by agencies in the U.S. and Britain, where SurControl is based.
This is the second acquisition Websense has pursued since late last year, when it acquired PortAuthority Technologies Inc. of Palo Alto, Calif. for $90 million.
Websense said at the time that its purchase of PortAuthority would "bring together two technology and market leaders in preemptive content security: PortAuthority with its information leak prevention technology and Websense with its ThreatSeeker malicious content identification and categorisation technology."
The result, the company said, would be a new best-of-breed security software company with the capacity to help organisations prevent the unauthorised use or disclosure of confidential data while simultaneously protecting users and data from external malicious threats.