Article 27 of Decree 214/1997 establishes the requirements to be met in terms of the composition of the animal research ethics committees:

Animal research ethics committees must be composed of a minimum of 3 people with experience and knowledge to ensure the welfare and care of animals, facilities and research procedures. The members who must be at least part of these committees will be the following:

• The animal welfare advisor of the centre.
• A representative of the quality assurance unit of the centre, when there is one, or failing that, a researcher from the centre not directly involved in the procedure to be reported.
• A person with experience and knowledge in animal welfare who has no direct relationship with the centre or the procedure in question.

Taking into account these requirements and the particular conditions of the centre, the CEEA has the following structure: