Corrections & Amplifications:

An executive at Penthouse-parent FriendFinder Networks said the magazine would continue to be printed for the foreseeable future, though he acknowledged uncertainty about its long-term prospects. An earlier version of this article and its headline incorrectly stated that the print edition of Penthouse would be discontinued. (1/20/16)

The glory days of gentlemen’s magazines are fading fast.

Penthouse Magazine, the long-running and raunchier rival of Playboy that has been in print for 50 years, said Friday that it will now be offered in digital format.

Photo: Bloomberg News

“Reimagined for the preferred consumption of content today by consumers, the digital version of Penthouse Magazine will combine and convert everything readers know and love about the print magazine experience to the power of a digital experience,” publisher FriendFinder Networks said in a statement.

Ezra Shashoua, FriendFinder’s chief financial officer, said the company plans to continue publishing the print magazine “for the foreseeable future,” though he acknowledged uncertainty about its long-term prospects.

The increased focus on digital comes just months after Playboy announced that it would no longer publish nude photographs as part of a broad redesign that will be unveiled in March.

Adult magazines have long struggled with adapting to the digital era. They were among the first media outlets to see their audiences slip away as wide varieties of adult content became available online.

Penthouse, which once sold over 5 million copies, has endured a rocky path over the past decade since founder Bob Guccione filed for bankruptcy in 2004 and lost control of the company. In 2013, FriendFinder Networks, which also operates a variety of adult social-networking sites, filed for bankruptcy and ceased being publicly traded.

Penthouse, whose print circulation regularly topped 5 million copies a month in its heyday, is no longer publicly audited. Playboy now has a circulation of about 800,000, down from a height of 5.6 million in 1975, according to the Alliance for Audited Media.

Penthouse will also shutter its New York offices and will be relocated to FriendFinder’s Los Angeles offices.

“This move will keep Penthouse competitive in the future and will seamlessly combine our unmatched pictorial features and editorial content with our video and broadcast offerings,” FriendFinder CEO Jonathan Buckheit said in the statement.

In recent years, Playboy’s parent company was also taken private and largely re-imagined as a licensing business after private equity firm Rizvi Traverse stepped in. Earlier this week, the company said it was putting the famed Playboy Mansion up for sale for $200 million, but with the understanding that the magazine’s 89-year-old founder would be allowed to stay for the rest of his life.

Write to Lukas I. Alpert at lukas.alpert@wsj.com