As of May 15, 2003, Belgian citizens who wish to travel to the United States under the Visa Waiver program must have a machine-readable passport issued by the Belgian Government.

The existing Belgian passport remain valid, but if used for travel to the US, you will need to apply for a Non-Immigrant Visa at the U.S. Embassy in Brussels before departure.
This measure is in effect for tourism and business travel.

Appointments for visa applicants must be made on an automated telephone system by calling 0903-99980.

As from October 1st, 2003, the US was going to extend its new Visa Waiver program.
Under the changes, passengers from countries participating in the program would have to present a machine-readable passport upon entry in the US.

Although the U.S. have now delayed this extension, it is STILL IN EFFECT FOR BELGIAN TRAVELLERS, meaning you need either a machine-readable passport or a non-immigrant visa for entry into the U.S.

The system will be extended at a later date to include travellers from Andorra, Australia, Austria, Brunei, Denmark, Finland, France, Germany, Iceland, Ireland, Italy, Japan, Liechtenstein, Luxembourg, Monaco, the Netherlands, New Zealand, Norway, Portugal, San Marino, Singapore, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
Since there is some discussion as to the applicability of the rules, we advise all foreign nationals to contact their local US Embassy for more details.

Belgian travellers who do not have a machine-readable passport yet should apply for a non-immigrant visa at the US Embassy.