The Ontario Ministry of Consumer Affairs alleges that the company broke Ontario's Payday Loans Act, which limits the fees payday loan companies can charge.
Cash Store Financial Services has 200 outlets in Ontario alone: branded as InstaLoans and The Cash Store.
They operate in 19 different communities in the province.
The Ministry of Consumer Services alleges the company is guilty of "several violations" the Act. It says Cash Store has charged customers interest rates higher than the maximum allowed, or charged prohibited fees.
The ministry is asking a provincial tribunal to revoke the company's licence.
Government officials are calling this a "major consumer protection enforcement action" and say they will release more information on Wednesday.
Executives at Cash Store's head office in Edmonton did not return calls from CBC News seeking comment.
The province brought in the Payday Loans Act in 2008 — designed to stop companies from charging exorbitant interest rates or hidden fees when lending money to the working poor.