Only the young scientists nominated by their respective national jury and submitted by the National Organiser can enter the EUCYS contest. In each country, the National Organiser is responsible for nominating/selecting the projects, and the participants, that will enter the EUCYS.

The contestants must conform to the following requirements:

• must be less than 21 years of age on the last day of the month of the EU Contest (September) but more than 14 years of age on the first day of the month of the EU Contest (September);
• have not completed more than one year of higher education studies at the time of the Contest;
• have not previously participated in the EU Contest, even if the project intended for presentation is different;
• have completed their project before entering university.

The projects may have been worked upon individually or as a team with 3 members max. The rules about age limit and scholarships are applicable to each participant involved with the project and are consulted in the regulation section. Should the participants enter as a team, all its members must be present in the EUCYS during the evaluation, so the Jury can truly ascertain the extent of their combined efforts.