Can my bank block my debit card if one of my accounts at that bank is overdrawn. The overdrawn account is not attached to my debit card. The account that is attached to my debit card has plenty of money.

There are a number of reasons a bank might block access on a debit card. The best source for information on what's going on is the bank and your deposit or debit card agreement with them. Call them and ask.

I did call them when my debit card was declined. They told me they blocked my card because another account I have at the bank was negative. The other account was not attached to my debit card. There's nothing in the cardholder agreement stating my card will be blocked if another acct I have is negative.

Obviously, none of us here knows what the bank's various contracts and agreements say. Nor do we know what state law might say on the subject. There is the concept of "set off," which in some states and under some circumstances allows a bank or other creditor to use money in one account to cover an overdraft in another.

Without knowing more about the specifics, I don't think anyone here will be able to opine whether or not what the bank appears to have done is permitted.

Is this a temporary or permanent block on the debit card?

Does your cardholder agreement state that the bank may limit or block use of the card if it feels the need to prevent losses?
If so, then this could be the reason, and would still abide by the cardholder ader agreement. A negative balance in an account represents a loss to the bank until it is paid off by the account holder.

One thing people sometimes seem to forget is that debit card access is a privilege, and the bank can revoke that privilege without denying you access to your funds. The reasons that they can revoke that privilege are outlined in the terms of the cardholder agreement that a customer agrees to when they sign up for an account and request a card.

Swedish Chef & "unregistered"... I would have preferred that my bank transferred the money from my account to cover my negative balance. It was an honest mistake on my part, I was out of town and didn't realize I was overdrawn. You don't need to imply that I'm a deadbeat using one account while my other account is overdrawn. Mistakes do happen...by customers and by bank personnel! I thought this was suppose to be a helpful forum. Sorry I bothered you all.

I apologize if I offended, however, you have to realize that people more often than not, are avoiding the inevitable. 99% of the time, customers will overdraw one account, abandon it, and use another account.

I'm going to sound like my grandfather here but, "If I've seen it once, I've seen it a thousand times".

To but a balanced spin on this, I think it's fair to say that the situations that attract bankers' attention are those like Swedish Chef describes. I still believe -- and perhaps I'm a bit of a Pollyanna here -- that most bank customers who err and create an overdraft are quick to make the needed deposit or transfer and are, quite frankly, embarrassed to have slipped up.

Just as bad news sells newspapers, problem accounts get banker's attention and are the ones that stick in the banker's memory banks. The customer that doesn't make waves -- a/k/a the "Good customer" -- often goes unnoticed.