The escape at the Porrentruy prison close to the French border came just days after the high profile escape of a convicted murderer and rapist, which sparked outrage in the alpine state.
"On Sunday, 3 July 2011 at around 12:40pm, after most of the detainees had been returned to their cells after lunch, two of them attacked the jailer and locked him up in a cell," said police from western Switzerland's canton Jura in a statement.
"They then went to the cell of a third detainee to free him. The three individuals then changed into civilian clothing and escaped," they added.
The jailer managed to raise the alarm after breaking the window of the cell, but it was too late.
Local police, border guards and the French military police have been alerted, and search dogs as well as a helicopter deployed in the manhunt.
"It is not excluded that the three fugitives have gone separate ways so as not to be noticed by police or others," said police.
Last Monday, a convicted murderer and rapist managed to elude his guards while taken out for a walk, leading to a massive search in the country.
The man identified as Jean-Louis B., who was described as extremely dangerous by police, was finally recaptured on Friday after he asked a restaurant worker to inform the police of his whereabouts.
Swiss media and the public were up in arms about the escape, with the biggest Swiss political party, the right-wing Swiss People's Party, calling for such "humanitarian" outings for dangerous criminals to be scrapped.