Greece

This visa is issued for up to 90 days and allows the holder to conduct business activities in Greece (such as attendance of business meetings, the creation of business contacts, and attendance of business seminars). U.S. citizens, nationals of Canada, nationals of European Union countries, Argentina , Australia, Bahamas, Barbados, Brazil, Brunei, Chile, Costa Rica, Guatemala, Holly See, Honduras, South Korea, Iceland, Israel, Japan, Malaysia, New Zealand, Nicaragua, Norway, Paraguay, Singapore, Switzerland, Serbia, Montenegro, Uruguay, Venezuela, Croatia and FYROM do not need a visa if their stay does not exceed 90 days. This is a single and multiple entry visas.

Citizens of all other countries are required to have a visa.
Visa requirements:
Passport should be valid 3 months after the date you exit the Schengen States
Completed signed visa application form
1-passport type photographs
An official invitation from the host company in Greece
Valid alien resident card or visa to the US
Bank and credit card statements for the last 3 months
Official Itinerary with closed dates of travel (flight reservation)
Visas of countries you will visit after you exit the Schengen State (if applicable)
The W-2 Forms for the last two years
Reference letter from employer stating position and monthly or annual salary