College students are being encouraged to sign up for debit cards rather than credit cards in an effort to avoid an early start toward a lifetime of debt.

With a debit card, which can be used for retail purchases and to get cash from ATMs, the money comes directly from a checking account. This way, students can't spend more money than they have.

Or can they?

One parent tells of a son whose use of a debit card racked up some $200 in overdraft fees because he thought he had more money in his checking account than he actually did.

Ed Mierzwinski, consumer advocate for the U.S. Public Interest Research Group, cites two problems with students using debit cards:

Even if you have no money in your checking account, debit cards typically still work. This means that if a student uses a debit card to buy just a $5 purchase, and the charge overdraws a checking account, overdraft fees of as much as $35 per transaction could mount. As long as the mistake goes unnoticed, additional transactions could accrue more fees.

Although your liability for credit card losses by federal law is limited to $50, if a debit card is lost or stolen, a thief can overdraw your checking account. And unlike with a credit card, a debit card transaction can cause money immediately to leave your checking account. So you may need to fight your financial institution to get your money back. With a debit card, a weak federal law lets you suffer unlimited losses if you fail to report the loss within 60 days after the bank statement containing the unauthorized use is mailed to you. Otherwise, your losses may be limited to $50 or $500, depending upon how soon you report it. Visa and MasterCard generally promise zero liability for fraud with their debit cards.

Even if you're particularly diligent, other issues -- some beyond your control -- may create debit card nightmares.

Some gas stations or other merchants may "block" say $50 or more on your checking account to make sure you have funds to cover a charge. This can make your checking account balance lower than your checkbook register indicates. Possible result: Surprise overdrafts.

Monitoring your checking account balance online or via an automated telephone system? Not all transactions or quoted balances may be completely up-to-date.

If you write additional checks after your debit card overdraft, a merchant who receives your check may charge additional separate overdraft fees.

So what should a student with a debit card do?

Log at least an extra $100 in your checkbook register, Mr. Mierzwinski advises. This can provide you with a buffer that could avoid an inadvertent overdraft.

Monitor your checking account regularly -- even before you get your statement -- for charges you didn't make. Report any fraudulent charges to your financial institution immediately.

Carefully scrutinize the terms of your checking account overdraft protection.

Is your account already overdrawn due to a debit card problem? Don't hesitate to ask your bank to waive all charges. Talk to a senior vice president, if necessary. If your checking account is closed due to your debit card usage, you may have problems opening any bank deposit account in the future.

Negative reports stay on file with Chex Systems Inc., the leading checking account consumer reporting agency, for five years -- unless you can persuade the bank or credit union that filed the report to request its removal.

For more information on how to get such a blemish removed, visit www.consumerdebit.com.