Mr Silk was made a club director in 1984 and became chairman in 1988, a position he held for four years.
He became president in 2003, taking over from the late Sir Bert Millichip.
Flags at The Hawthorns have been lowered to half mast and a minute’s applause will be held before the match against Newcastle later, the club said.
Chairman Jeremy Peace told the club’s official website: “John was very proud to be club president and took his duties very seriously.
“Until his illness, he was a constant presence at home and away matches.
“John was a quiet but very honourable man and he will be greatly missed. Our thoughts are with his family and friends at this difficult time.”
