I understand cash advances accrue interest from the very second they're made, but I don't understand why my credit card company continues to charge me cash advance interest after I've paid my account in full. Example: My last cash advance was made on January 27th. My billing period runs from January 9 thru February 8th. I pay my account balance in full (down to $0.00) every month by the 5th, so on February 5th, my account balance was $0.00. I received a cash advance interest charge on February 7th. I assumed this was the amount of the daily interest accrued from my January 27th cash advance thru the date my account was paid in full, which was on February 5th. I haven't made any additional cash advances on my account since January 27th. However, on March 8th, I received another cash advance interest charge, even larger than the one on February 8th. My credit card company says the second charge is "residual" interest. How can I be charged "residual" interest larger than the original interest charge? And, what could they base it on, as the account was paid in full after the last transaction was made. Shouldn't the interest accrual stop when the account balance goes to zero? I'm beginning to think my credit card company isn't stopping the interest when my account is paid to $0.00, but letting it run for an entire additional billing period. Anyone experienced anything similar? Any suggestions? I'm still arguing with the credit card company, but they refuse to provide account details.