"Today it is with deep heartfelt sadness that AC/DC has to announce the passing of Malcolm Young," AC/DC wrote in a statement.
"Malcolm, along with Angus, was the founder and creator of AC/DC. With enormous dedication and commitment he was the driving force behind the band. As a guitarist, songwriter and visionary he was a perfectionist and a unique man. He always stuck to his guns and did and said exactly what he wanted. He took great pride in all that he endeavored. His loyalty to the fans was unsurpassed."
Angus Young added, "As his brother it is hard to express in words what he has meant to me during my life, the bond we had was unique and very special. He leaves behind an enormous legacy that will live on forever. Malcolm, job well done."
The Young brothers lost their older brother George Young, the Easybeats guitarist and AC/DC's longtime producer, in October at the age of 70.
In an additional statement from Malcolm Young's family, the band said that Malcolm Young died peacefully Saturday with his family by his side.
"Renowned for his musical prowess, Malcolm was a songwriter, guitarist, performer, producer and visionary who inspired many," the statement said. "From the outset, he knew what he wanted to achieve and, along with his younger brother, took to the world stage giving their all at every show. Nothing less would do for their fans."
As rhythm guitarist for the legendary rock band, Malcolm Young served as an indispensable foil to Angus Young's arena-stuffing riffs. After forming AC/DC in 1973, the Young brothers would be credited as co-writers on every song the band recorded from their 1975 debut High Voltage through 2014's Rock or Bust. That final album marked AC/DC's first without Malcolm, who announced in September 2014 that he would permanently leave the band due to dementia.
"We miss Malcolm, obviously," AC/DC singer Brian Johnson said in July 2014. "He's a fighter. He's in [the] hospital, but he's a fighter. We've got our fingers crossed that he'll get strong again... Stevie, Malcolm's nephew, was magnificent, but when you're recording with this thing hanging over you and your work mate isn't well, it's difficult. But I'm sure [Malcolm] was rooting for us."
Malcolm Young last performed live with AC/DC when their tour for 2008's Black Ice concluded in June 2010 with a concert in Bilbao, Spain.