Tarek Loubani and John Greyson were detained Aug. 16 amid deadly riots in the Egyptian capital. They had been trying to make their way to Gaza, where Loubani was to teach emergency room medicine and Greyson was considering producing a documentary.
Canadian foreign affairs officials have said it appeared the men were in the wrong place at the wrong time.
Lawyers representing Loubani and Greyson had been hoping to meet Thursday with a Cairo prosecutor to plead their case for release.
Loubani is a doctor from London, Ontario, and Greyson is a Toronto filmmaker and university professor.