It is best to wait for six months to a year before applying for a credit card after rejection. This is because when banks make a hard enquiry of your credit score, your credit score will fall. Banks do an enquiry every time you apply for a credit card. If you apply for a credit card immediately after a rejection, your credit score can fall. Taking a six-month or a year gap can also help you rectify the error for which the credit card is rejected and improve your credit score.