January 1, 2009 is the effective date of the agreement with the Czech Republic.

On May 1, 2016, a supplementary agreement entered into force. The supplementary agreement exempts workers who, by virtue of the original agreement, are not responsible for contribution to the Czech old-age, survivors, disability, and unemployment insurance programs, from paying taxes that fund the Czech health insurance program.

January 2009 is the earliest possible month of entitlement to Czech Totalization benefits. Both the United States and the Czech Republic may use periods of U.S. and Czech Social Security coverage earned prior to January 1, 2009 to establish entitlement to U.S. or Czech Totalization benefits.