Alex died suddenly and unexpectedly on September 6th, 2007 from arteriosclerosis. His health check earlier in the week had given him a clean bill of health and shown normal asper and cholesterol levels, making his death especially tragic and out of no where. Even more depressing is the fact that his last words to Pepperberg the night before were "You be good. I love you." Alex is survived by two other birds within the project, Griffen and Arthur, though they are much younger and less advanced.
Dr. Pepperberg published a memoir about Alex and his accomplishments, titled Alex & Me: How a Scientist and a Parrot Discovered a Hidden World of Animal Intelligence--and Formed a Deep Bond in the Process in 2008.