He was 67.
The English musician, who was the only member of the band to appear on every album released from 1969 to 2014, passed away on June 27.
Current Yes keyboardist Geoff Downes tweeted the sad news.
"Utterly devastated beyond words to have to report the sad news of the passing of my dear friend, bandmate and inspiration Chris Squire. #yes."
Yes posted on its official Facebook, "It's with the heaviest of hearts and unbearable sadness that we must inform you of the passing of our dear friend and Yes co-founder, Chris Squire. Chris peacefully passed away last night in Phoenix Arizona, in the arms of his loving wife Scotty."
"Because of his phenomenal bass-playing prowess, Chris influenced countless bassists around the world, including many of today's well-known artists. Chris was also a fantastic songwriter, having written and co-written much of Yes' most endearing music, as well as his solo album, 'Fish Out of Water'."
Squire, who formed Yes in 1968 with Jon Anderson, revealed that he was diagnosed with acute erythroid leukemia back in May.