In August 1999, NAE invited 60 professional engineering societies to solicit nominations from their members for the greatest engineering achievements of the 20th century. From the assembled nominations, each society then submitted their top five to the NAE in October. Twenty-seven societies submitted a total of 105 nominations.

The chief criterion for nominations was the impact of the engineering achievement on quality of life during the 20th century.

The NAE formed a selection committee made up of leading engineering experts from academia, industry, government, and a wide range of engineering disciplines. To avoid undue influence on the process, the names of the committee members were not released until after the final selections were made.

From the initial 105 nominations, the committee selected 48 nominations for final consideration. These 48 were grouped into larger categories. For example, specific innovations in building bridges and roads were combined under "highways," and the tractor, combine, and chisel plow were combined under "agricultural mechanization." This reduced the number of nominations to 28, and the committee met in December 1999 to select and rank the top 20.

On February 22, 2000, former Apollo astronaut and NAE member Neil Armstrong announced the list in a speech at the National Press Club in Washington, D.C.