There are a number of reasons for being denied credit, such as a history of paying late or slowly, having had collection procedures initiated against you, or having filed for bankruptcy. Having too many credit cards can be another. Even if you don't use the cards, they represent credit that's available to you. If that credit becomes too high a percentage of your salary, no one will want to loan you money. A creditor may even refuse you credit if you've had too many credit inquiries over the past few months, because that may mean you've got multiple applications for credit being applied for simultaneously.