Police allege the men used fraudulent debit and credit card terminals to steal people's card information as they made legitimate transactions in stores.
The investigation started following a tip in July that a card-skimming operation was going on across the Prairies. Police used video surveillance to identify four suspects.
The frauds allegedly happened in Alberta, Saskatchewan and Manitoba, but police said they determined the group was based in Saskatoon.
While executing a search warrant at an apartment in the city last Thursday, police said a man, 41, returned to the residence and was promptly arrested. A second man, 39, was arrested this morning.
Both men now face fraud charges.
Police found numerous items that they believe were fraudulently obtained. They also found two firearms that had not been secured, as well as some ammunition.
Police are continuing to investigate and have now asked for warrants for three other men they believe are involved.