Pirates General Manager Neal Huntington said the right-hander's contract extension includes a club option for 2017.
Terms of the deal weren't announced but the Pittsburgh Post-Gazette it is for $21 million. Morton would have been eligible for free agency following the 2014 season.
Morton, 30, went 7-4 with a 3.26 ERA in 116 innings over 20 starts last season for the Pirates after returning from elbow ligament replacement surgery in June.
He was particularly effective late in the season during the Pirates' playoff push, going 4-1 with a 2.67 ERA in his final 11 outings.
Morton sports a 30-49 mark with a 4.70 ERA over 109 career games with the Atlanta Braves and Pirates.
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