All 26 stores including the Center City, Ardmore, and Wayne locations are being shuttered.
The Boston-based athletic gear retailer is selling its assets to a group known for buying struggling companies after failing to find a buyer willing to keep its stores.
City Sports, which filed for bankruptcy in October, plans to hold going-out-of-business sales starting Friday.
A declaration filed by company officials says harsh weather last winter and stiff competition pushed the company into bankruptcy.
Its assets will be sold to Hilco Merchant Resources LLC, a unit of Hilco Global of Northbrook, Illinois, and Gordon Brothers Retail Partners LLC of Boston.
In an email to customers Thursday, with the subject line 'It's been a good run,' City Sports thanked them and those who wore ubiquitously popular t-shirts.
"Thank you to every customer who stepped through our doors. We know there are a lot of you because you can't walk around Boston, Providence, Burlington, New York, Philadelphia, Baltimore, DC, or any airport in America without seeing those iconic City Sports t-shirts. We love serving you and we will miss you."
The Associated Press contributed to this report.