The visa application process can take 8 months or more, so we encourage attendees from countries other than the United States to apply for visas as early as possible, but no later than 3 months before they wish to enter the United States. Please note that a visa does not guarantee entry into the United States!
Individuals may request a letter of invitation by submitting a Help Ticket
or by fax +1 202.416.6100. Please include the meeting name, your full name as it appears on your passport, as well as your gender, date of birth, complete mailing address, passport number and country of issue, and phone and fax numbers. OSA is not able to contact US embassies in support of an individual attempting to gain entry into the host country to attend a meeting or conference.
For detailed information about applying for a visa, refer to the US Department of State web site
Attention Nationals and Citizens of Visa Waiver Program countries:
Electronic System for Travel Authorization (ESTA)
As of 12 January 2009, all nationals and citizens of Visa Waiver Program (VWP) countries will be required by law to obtain a travel authorization prior to initiating travel to the United States under the VWP. This authorization may be obtained through the Electronic System for Travel Authorization (ESTA), a free internet application administered by the Department of Homeland Security through a US government web site.
Register online for entry to the United States under the VWP Visa Waiver Program Frequently Asked Questions