Maldives ex-president Gayoom, 80, was arrested on Monday night as the government cracked down on political figures.
Maldives President Abdulla Yameen declared a 15-day state of emergency in the country on Monday as troops stormed the Supreme Court.
"I have not done anything to be arrested," Gayoom said in a video message to supporters posted on Twitter.
Maldives police also arrested President Yameen's estranged half-brother.
The charges against Maumoon Abdul Gayoom include bribery and attempting to overthrow the government, his lawyer said.
Gayoom was president of Maldives from 1978 to 2008.