The move comes after the troubled sports chain lost the franchise to sell Rangers merchandise to Mike Ashley's rival Sports Direct.
Wigan-based JJB has been battling for survival for a number of years. It employs 4000 people and has a network of 180 stores including dozens in Scotland where hundreds of staff work.
Last year it persuaded landlords to agree a restructuring plan which included the closure of 41 stores and company chiefs had hoped to secure vital funding to turn the business around.
But today the firm admitted it would not be able to raise sufficient financial support.
A statement said: "As a result, the board has decided to conduct a formal sale process of the company and now wishes to invite offers to support further investment in the company, which may result in a sale of the company or its assets."
JJB has debts and outstanding loans totalling £36million and given the level of current borrowings it said there "can be no assurance that any proposal or offer that may be made would attribute value to the ordinary shares of the company".
Matthew McEachran, a retail analyst at Singer Capital Markets, said JJB's big rivals Sports Direct and JD Sports Fashion were now poised to pick up a chunk of the store estate.
He said: "On the assumption a sale is unlikely, the next step is likely to be administration."
The announcement comes four months after it secured £20m from US retailer Dick's Sporting Goods and a further £10m from existing shareholders.