Nothing spoils a happy holiday quite like opening your monthly credit card bill and seeing charges for purchases you never made.

It might be a clerical error, but more likely it's an indication that someone has stolen your credit card number.

"Credit card fraud increases significantly during the holiday season," said Robert Flashman, Extension family resource management specialist in the UK College of Agriculture. "We usually think of credit fraud happening when a thief steals your purse or wallet with cards inside, but the thief really only needs your credit card number."

Flashman said one way of preventing theft is to never give your card number over the telephone unless you initiated the call yourself.

"If the call comes into you," he said, "you have no way of knowing the identity of the person on the other end of the line. That individual may be falsely representing a company, or say they're with a company you find out later doesn't exist."

Flashman offered other suggestions for preventing credit card fraud:--sign credit cards immediately when they arrive in the mail;--if a purchase is rung up incorrectly at a store, ask for the incorrect charge slip and then destroy it;--keep copies of all sales slips and compare them to charges on your monthly bill.

"If you find unauthorized purchases on your bill," said Flashman, "contact the credit cardissuer immediately by phone. Tell them to put a stop on the use of the card and have them issue you a new one. Then follow-up by mail with a letter stating the facts, the date and time, and the person you talked to."