The Netscape Navigator browser will no longer be supported by owner AOL from 1 February because of a lack of users.
The AOL announcement means existing users will no longer receive any security updates or any extra functions to their browser.
AOL is encouraging existing Netscape users to migrate to the open source Firefox browser, the closest rival to the dominant Internet Explorer browser from Microsoft.
In the mid-1990s, Netscape was the dominant browser, before Internet Explorer, which was bundled with the Windows operating system, pushed it aside.
This led to Netscape starting a long-running legal case, which alleged that Microsoft was acting in an anti-competitive manner.
Despite winning some concessions from Microsoft, Netscape never recovered and AOL's acquisition of the company in the late 1990s made no improvement in its fortunes.
Internet Explorer has about 80% of the browser market, with Firefox holding about 15% - Netscape has less than 1%.
A number of former Netscape developers are involved in the Firefox open source project.