Credit card companies can no longer charge customers for going over their limit unless they agree. And companies must provide 45 days notice of an interest rate increase.
Credit card companies must also include on statements how long it will take to pay off your balance.
Pamela Banks with the Consumers Union said, "What it means for consumers is that they will have the information they need in order to better manage their credit card."
The changes will cost credit card companies an estimated $50-billion dollars over the next five years.
So many credit card companies have started raising interest rates, and charging new fees for things like paper statements and overseas transactions.
Another big change will affect customers under the age of 21. People under 21 will not be able to open up a credit card unless they have a co-signer or show they have enough income to pay.