Police have been looking into the case for two-months and say Nicole Bizier, 32, was arrested Sunday.
Authorities received complaints dating back to January that Bizier faked veterinary records and was selling dogs without vaccines.
Animal welfare agents told her in February to stop selling dogs, but they continued to receive complaints from owners. Agents said they found seven pitbull puppies and four adult dogs.
Bizier was arrested and is being charged with theft by deception, cruelty to animals, and illegal operation of a pet shop.
Skowhegan police are asking anyone with more information to contact them.