The society says the “bold new brand identity” is a “radical change of image” for the business.
It also has a new purple and green logo.
The society has started a major investment programme to modernise its branch network over the next 18 months.
Robert Sharpe, chief executive of West Brom, says: “This radical change of image represents an exciting new era for the West Brom, with a revitalised brand and fully refurbished branch network that members, staff and local communities can be extremely proud of.
“Our new identity retains the symbol of the tree with its connotations of strength, resilience and growth, while in branches the emphasis is very much on making members feel welcome and valued.”
The society recently announced its half-year results for the six months ended September 30 2010.
It reported a £5.5m loss, down from the £11.7m a year ago.
Mortgages in arrears were 1.27%, below the Council of Mortgage Lenders average of 1.55%.