The riot at the Litoral Penitentiary in the city of Guayaquil reportedly began on Friday evening.
Police tactical units who entered the prison buildings found guns, explosives and blades, reports say.
Officials say they have re-gained control of the jail.
Nearly 300 inmates have died so far this year in the country's prisons, and September's gang-related violence was the worst in Ecuador's history.
Some 119 inmates lost their lives during a riot in the Litoral Penitentiary on 28 September.