The sale is somewhat unique because pay-TV channels are often reluctant to sell their shows to another pay service. HBO, for example, does not sell its shows to Netflix.
Under the terms of the deal, Showtime will still be able to telecast episodes of "Dexter" on its network as well as make the show available on its digital platform Showtime Anytime.
CBS, which owns Showtime, is also selling reruns of "Dexter" to a basic cable network.
Still, Netflix can claim it has a show that its online rivals Hulu and Amazon Prime don't have.
Follow Joe Flint on Twitter @JBFlint.