Calling Mongolia from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 976 - Country Code for Mongolia
• Phone Number (may not begin with 0):
  • fixed - 8 to 9 digits, comprising the following:
    • single digit carrier code - Mongolia TeleCom and Mongolian Railway Authority with carrier codes 1 and 2 respectively
    • area code
    • local number
  • cell phones - 8 digits
  • VoIP - 8 digits, first digit is 7
• sample call from US to a landline inn Ulaanbaatar: 011 976 11 ??? ???

How to dial to Mongolia cellular:

• dialing format for calls to a cell phone: 011 976 X ??? ????
• X can be 5 (fixed wireless only), 8 or 9

Phone Books:

• Mongolia Yellow Pages