The defence ceremony of a doctoral thesis is a public occasion. Those concerned arrive in the hall in succession so that the doctoral candidate enters first, then the custos followed by the opponent. The audience stands up.

The doctoral candidate, custos and opponent wear tailcoats and dark waistcoats, while women use black dresses (not long ones). The custos and the opponent, if they have the doctor's degree, hold their doctoral hats in their hands when they enter or leave the hall. For the duration of the ceremony, the hats are laid on the table, with the lyre signs facing the audience.

As soon as everyone is in position but still standing, the custos opens the ceremony. Everyone but the doctoral candidate is then seated.

The candidate, standing, gives his lectio praecursoria, which shall not last longer than 20 minutes. He starts his speech by saying: "Dear Custos, Dear Opponent, Ladies and Gentlemen." If need be, the custos will advice him on the content and nature of this speech.
After this opening lecture, the doctoral candidate says: "I am asking you, Professor/Docent/Doctor ..., as the opponent appointed by the Faculty, to put forward the comments occasioned by my dissertation."

The opponent, standing, presents a brief statement dealing with the scientific position and significance of the topics of the dissertation and other general questions of the same nature. After the statement, the opponent and the doctoral candidate are seated.

In the beginning of the actual examination, the opponent will first focus on formal and general matters, followed by a more detailed scrutiny.

The opponent may use a maximum of four hours for his examination to allow sufficient time for the potentiality of further opponents. If the examination lasts longer than four hours, there will be a break announced by the custos. The whole ceremony shall not last longer than six hours. At the end of his examination, the opponent stands up presents his final statement, with the doctoral candidate standing and listening. The doctoral candidate, standing, gives his thanks to the opponent.

The doctoral candidate turns to the audience and says: "I now request that anyone present having objections to my doctoral thesis ask Mr/Mrs Custos for permission to speak."

The custos acts as moderator, making sure that the doctoral candidate is allowed to respond to every point of criticism immediately and that those speaking keep to the point. In his statement to be given to the Faculty, the opponent will also consider the points raised by the audience in the defence ceremony.

Standing, the custos closes the ceremony by saying: "I declare this defence ceremony closed."

English version by Vesa Komulainen