The deal is worth $12.25 million, a source confirmed to ESPN's Jerry Crasnick. The deal includes a base salary of $4.1 million in 2016 and $4.15 million in 2017, as well as a signing bonus of $4 million.
FoxSports.com was first to report the deal.
Clippard, who turns 31 later this week, went 5-4 with a 2.92 ERA and 19 saves last season with the Oakland Athletics and the New York Mets. The two-time All-Star joins an Arizona bullpen that features closer Brad Ziegler, who had a career-high 30 saves last season, and converted starter Daniel Hudson, who posted a 3.86 ERA last year in his first full season as a reliever.
Clippard helped stabilize the Mets' bullpen last season while leading into closer Jeurys Familia after he joined the club in a July 27 trade with the Athletics. He allowed one run in 19 2/3 innings over his first 20 appearances while serving as Familia's primary setup man.
Clippard took a step backward in the final weeks of the regular season and the postseason. He had a 6.75 ERA in eight postseason appearances.
Nonetheless, he was the only pitcher in the majors to appear in at least 69 games in each of the past six seasons.
ESPN.com Mets reporter Adam Rubin contributed to this report