The doctoral defense is the final milestone in the program. After you have finished the dissertation, or when you are close to finishing it, you should set a defense date with your doctoral committee. The defense must be publicly announced no later than ten days in advance, and by the time of the announcement the dissertation should be in a final draft stage. To schedule your doctoral defense including reserving a room and announcing your defense, submit the Doctoral Defense Scheduling Request form. 

During the defense, your will present your dissertation research in a 45-minute presentation. During and immediately after the presentation, your committee members can ask you questions about the content of the paper and presentation. After that, other members of the audience may ask questions also.

When there are no more questions, the dissertation committee will meet to discuss your work, and will render a decision immediately. Note that the committee may ask you for revisions.

After the exam, you need to fill out a form. Contact the Department Office for digital versions of required forms.

Important! The deadline for filing your dissertation is not the last day of the quarter! Make sure you file your dissertation with the University in its final formatted form, approved by your committee and have filed all your dissertation defense paperwork no later than the deadline specified on this page. If you fail to meet this deadline, nothing the department or your advisor can do will fix it and your degree date will be pushed to the following academic term. This is especially important if you have a job lined up that requires the PhD or you are nearing the maximum time in the program of 6 years.

What the UCI Catalogue has to say

The UCI Catalogue is the sole authoritative source on academic requirements. About the doctoral defense, it says this:

Requirements for the Ph.D. The requirements for the Ph.D. degree are (1) the student must formally present and defend a written dissertation proposal to a committee of at least three members selected according to Graduate Division requirements. The dissertation proposal presentation may take place as part of the examination for Advancement to Candidacy, in which case, that five-member committee will jointly consider approve the dissertation proposal; (2) the proposal must be approved prior to the final dissertation defense (usually at least three months before to allow time for the candidate to incorporate suggestions and changes required by the committee); (3) the accepted proposal must be archived with the department; (4) prior to the approval of the final version of the dissertation the student is expected to defend the dissertation in a public colloquium announced with at least two weeks’ notice; and (5) all requirements for the Ph.D. degree must be fulfilled within three years after advancement to candidacy.