800-829-7650

They won't always send you a Certified Letter until you are one step away from being automatically assessed.

It's not a scam - they send you a notice with this number on it FIRST and THEN they will contact you to schedule a conference.

Carla, stop posting "this is not a scam", all you are doing is posting bad advice.
Even the IRS says your advice is bad:
http://www.irs.gov/uac/Tax-Scams-Consumer-Alerts

While the phone number may be legit, criminals can and do spoof their caller ID to trick people into thinking it is a legit call.

NEVER accept a call or any form of a message from someone claiming to be the IRS at face value.
If you receive a call from someone claiming to be with the IRS, STOP!
Ask the person for their employee badge number and the reason for the call, the person will acknowledge your request and fully comply IF they are a real IRS employee. If they do not comply or demand money, demand personal information, and/or threaten arrest, THEY ARE NOT FROM THE IRS!
Once you have that information tell them you will call back on an IRS office phone number.
See:
http://www.irs.gov/uac/How-to-Contact-the-IRS-1

From:
http://www.irs.gov/uac/Report-Phishing

You receive a phone call or paper letter via mail from an individual claiming to be the IRS but you suspect they are not an IRS employee …

Phone call:

  Ask for a call back number and employee badge number.
  Contact the IRS ( http://www.irs.gov/uac/How-to-Contact-the-IRS-1 ) to determine if the caller is an IRS employee with a legitimate need to contact you.
  If you determine the person calling you is an IRS employee with a legitimate need to contact you, call them back.

Letter or notice via paper mail:

  Contact the IRS ( http://www.irs.gov/uac/How-to-Contact-the-IRS-1 ) to determine if the mail is a legitimate IRS letter.
  If it is a legitimate IRS letter, reply if needed.

Report the incident to the Treasury Inspector General for Tax Administration if the caller or party that sent the paper letter is not legitimate.

1(202)657-5868 fake calls

I called another IRS office asked if the number i received was good or not..He said no it was a scam..  Just call another IRS office to get if this is a scam  or a real..

Why be on hold with the irs for over an hr if your open till 9.

Not sure who it was

i got a call too! I am not sure what to think ?
But, I do know the IRS does not call people on their cell or regular phones.
Do not be fooled !!

I can vouch for your cut because I am currently on hold and I've been on hold for one hour and 51 minutes.

IS THIS REALLY THE IRS OF KANSAS CITY, MO?

No.

The irs has been helpful, WHEN YOU CAN GET THROUGH TO THEM.  Which is it?  7am-7pm, for which time zone???  7am-8pm for local time zone?

Well i just got a bogus letter and i just got done with a tax exemption in 2016 from a state i live  in then i get a bogus letter from a state i never live in  luckily i was able to get a hold of the irs from where i used to live  and i even talk  to the same guy i did my tax exemption told him how i got this letter well he told me to file through attorney general and BBB report both places where you filed a tax return recently with a suspiciousness  of a so call IRS employee doing something odd with your paperwork  so both places are going to be look into.so i get this call with a bogus letter

Received certified letter stating it was IRS owing them money