Visa Information

Do you require an official letter of invitation to initiate the visa process?

Please read the information below to determine if an invitation letter is required.

It is never too early to start working on getting your visa. It can take as long as four months to get a visa to enter the United States. Please check with your local American Embassy or Consulate to obtain the necessary documents as soon as possible. IADR encourages applicants to bring their English-language resume with a list of their published articles and research topics to the interview as well.

All international visitors must present a passport or secure document when entering the United States. Most travelers to the United States must hold a valid visa and a passport that is valid six months longer than the intended visit. For a more thorough review of the visa process, please consult the U.S. Department of State website.

The purpose of the visit determines what type of visa will be needed. Visitors planning to visit or attend a meeting will most likely apply for a Business (B1) visa.

The Visa Waiver Program (VWP) allows citizens of participating countries to travel to the United States without a visa for stays of 90 days or less, when they meet all requirements. Travelers must be eligible to use the VWP and have a valid Electronic System for Travel Authorization (ESTA) approval prior to travel. If you are eligible to travel on the VWP, but prefer to have a visa in your passport, you may still apply for a visitor (B) visa. Transiting or traveling through the United States to Canada or Mexico is generally permitted for VWP travelers. The following are examples of activities permitted while in the United States on the VWP:


  • Consult with business associates.
  • Attend a scientific, educational, professional, or business convention or conference.
  • Attend short-term training (you may not be paid by any source in the U.S. with the exception of expenses incidental to your stay).

You must be a citizen or national of VWP-participant country. Please click here to see if your country participates in the VWP.

Citizens of Canada traveling to the United States do not require a nonimmigrant visa, except for the travel purposes described below. Canadian citizens who are inadmissible to the United States under immigration law, or have previously violated the terms of their immigration status in the United States can Learn More about ineligibilities related to Canadians on the CBP website. Canadian citizens with ineligibilities also have the option of applying for a visa and a waiver at the nearest U.S. Embassy or Consulate if it is more convenient for them.

Citizens of Bermuda traveling to the United States do not require a nonimmigrant visa for travel up to 180 days, except for the travel purposes described below. Additionally, Bermudian citizens do not require a visa unless they are ineligible for a visa under U.S. immigration law, or have previously violated the terms of their immigration status in the U.S.

More information on applying for visas can be found on these websites:

Travel to the United States – National Academy of Sciences

Visa fees

Visa application status

Upon completion of your registration, invitation letters will be sent by email as a PDF attachment. If you require an additional printed letter sent by first class international mail, additional fees will apply. Please contact [email protected] with any questions. In the event of a cancellation of registration, express shipping fees for invitation letters are non-refundable (for both delegates and accompanying persons).


Only registered delegates and accompanying persons attending the General Session are eligible to receive invitation letters.