Aaron Lane Cook (born February 8, 1979, in Fort Campbell, Kentucky) is a right-handed Major League Baseball starting pitcher for the Colorado Rockies. He has played with the Rockies for his entire Major League career.

In high school Cook allowed only one home run, to current Red Sox third baseman Kevin Youkilis, who was playing for Sycamore High School in suburban Cincinnati.

Cook saw his 2004 season come to an abrupt end when it was discovered that he suffers from pulmonary embolism, or blood clots. During an August 7 start against the Cincinnati Reds, Cook complained of dizziness and shortness of breath. After he was taken to a local hospital, doctors discovered blood clots had formed in his right shoulder. On September 10, Cook underwent extensive surgery at a St. Louis hospital during which the first rib on his right side was removed to relieve compression on a major blood vein.