Yes, you can use Frontline Flea and Tick Treatment for both cats and dogs. However, they are separate products - they have one product for dogs and one product for cats. There are also separate types for puppies/kittens versus adult dogs/cats.
You can use this product for both just make sure get the right one for the right animal. If you are not sure which one,ask a pet professional they know which one you can use make sure you tell them if it's a dog or cat.