Evans, a former school teacher, starting working at The Hawthorns in May 1989 - after holding similar roles at Northampton Town and Nuneaton Borough.
In July 2002 - Evans then became the first Baggies club secretary to become a director - a position he held until he retired back in 2007.
However, despite retiring he still regularly attended games as a season ticket holder.
In a tribute following the news, the club said in a statement: "A trusted, knowledgeable and dedicated club servant, the Tipton-born executive held an important role during a period of great change at The Hawthorns and earned widely-held respect from football clubs across the English Football League.
"His 18-year term makes him the third-longest serving Club Secretary in Albion history, with only Fred and Alan Everiss having held the title longer.
"The club sends its heartfelt condolences to the Evans family at this difficult time."