TMZ reports Frey was struggling with intestinal issues for months, and took a turn for the worse in the last few days.
After his death, the band released a statement on Facebook, writing, "It is with the heaviest of hearts that we announce the passing of our comrade, Eagles founder, Glenn Frey, in New York City on Monday, January 18th, 2016. Glenn fought a courageous battle for the past several weeks but, sadly, succumbed to complications from Rheumatoid Arthritis, Acute Ulcerative Colitis and Pneumonia."
The band went on, "The Frey family would like to thank everyone who joined Glenn to fight this fight and hoped and prayed for his recovery. Words can neither describe our sorrow, nor our love and respect for all that he has given to us, his family, the music community & millions of fans worldwide."
In December, Frey and the Eagles were scheduled to make an appearance at the Kennedy Center Honors event, but pulled out due to his health.
When they cancelled, the band said that Frey needed to undergo surgery that would require a long recovery process. He had the surgery in November, but it doesn’t seem like he was ever able to recover.
The Eagles are among the Top 20 best-selling music acts of all time. Frey was part of the band when it released the number-one hits “Best of My Love,” “One of These Nights,” “New Kid in Town,” “Hotel California,” and “Heartache Tonight.” When the Eagles broke up in 1980, Frey went solo and scored several Top 40 hits, including “The Heat Is On” and “You Belong to the City."
In 1994, he joined the Eagles for their Hell Freezes Over reunion tour. He released his final solo album, “After Hours,” in 2012.