I received a text message first, telling me to call that number and that my debit card may have been comprimised. I ended up calling the number on the back of my debit card and they told me exactly what was in the text message and voicemail.
 Oct 08th, 2013
If you get this message, you are going to want to call the CHASE DEBIT card number on the BACK of your card. We called the number on the back of our card and they transferred us to the FREUD department for Chase. Our card HAD been compromised. So, if you get a call from this phone number don't answer the call, instead call Chase Debit card and they will help you.
 Feb 06th, 2013
Chase Debit card fraud prevention
 Aug 22nd, 2012
I thought this number was very suspicious (see my earlier comments), but today I called the number of Chase's website and they connected me to their fraud prevention dept at 800-978-8664. They did confirm that there was activity on the card they wondered about, and I asked the person about the (800) 355-5265 number. She confirmed that number was used by the automated system, but agreed that the best approach was the one I took--to call a known good number, like the one on the site or the back of the card.
 Jan 17th, 2012
I answered. Caller informed me that I have suspicious activity on my credit card and asked for my personal information. (I didn't give it to him.) Here's the kicker. I have never had a credit card in my life and do not plan on getting one any time soon.
 Sep 10th, 2011
(800) 848-9380 has been repeatedly calling our business. When the phone was answered the line went dead. When called back the pre-recorded message identified the call as from CHASE Bank and requested an account number or Social Security number [RED FLAG!].

I called CHASE Fraud Prevention Department @ 800-978-8664. They informed me that this number has NO connection with CHASE Bank. They will make a report but there is not a lot they can directly do to protect the individual – it’s up to you.

Be safe ~ Be smart ~ Be alert
Miss T
 Oct 05th, 2010
Chase called me after they noticed there were several attempts on my card used at a gas station in a city I've never been too. Should not use debit cards anymore!
 Dec 04th, 2009
It is a legitimate number. I didn't call back because people were saying it was fraudulent, then went to buy something and had my card declined. If you don't trust them, call the number on the back of your debot card and they will transfer you, but will clarify it is the correct number. Save yourself the embarrassment of having your card declined in a long line of customers!
 Oct 11th, 2009
I too called the number on the back of my Chase card regarding the 800.978.8664 number. It is the Chase debit card fraud prevention department. I had made an expensive purchase that was unusual for me and they were callign to make it was me that made the purchase. And, they called within 20 of the purchase. I greatly appreciated it!
 Aug 13th, 2009
It seems there is more than one number - I received a call today from 877-572-0188. I was not available so they left a message. When I called it and an automated system asked for my debit card number, I hung up and investigated. I called the number on the back of my card and talked to a telephone banker who transferred me to the "debit card fraud prevention" office. Before transferring, she gave me their direct number as 800-978-8664. That office confirmed that they DID call my home to ask about a number of recent transactions. She ran through the transactions and all were legit (although a couple were big and out of the ordinary for me). So, the bottom line is that it was a legitimate call from Chase, although I agree with the general advice not to give out your info unless YOU have initiated the call to a verified legitimate number.
 Sep 17th, 2008
800.978.8664 is a legit number from Chase debit card fraud prevention department. They called me and left a message when they detected suspicious activity in my account. I called Chase at the main number printed on the back of my debit card and confirmed that 800.978.8664 is from their debit card fraud prevention department. They then transfered me to that department and there was a pending charge on my business account that I didn't make.
 Sep 10th, 2008
Called the number printed on the back of my card, and asked them for the "Debit Card Fraud Prevetion Dept". The number THEY gave ME matched: 800-978-8664
 Dec 20th, 2007