The unnamed man, from Dundalk in Ireland, was arrested just across the border in Newry, in British-ruled Northern Ireland, on Monday by police investigating the Real IRA bombing, in which 29 people were killed and more than 200 wounded.
A spokeswoman for the Police Service of Northern Ireland on Tuesday said the suspect had been "charged with supplying a maroon-coloured Vauxhall Cavalier to terrorists between 11-16 August 1998".
The spokeswoman confirmed the car was the one in which the Real IRA hid a 225-kg bomb which exploded with devastating effect in the Northern Irish market town.
Upcoming court appearance
The man is due to appear before magistrates in Enniskillen, in the west of the province, on Wednesday.
The Real IRA is a breakaway faction opposed to the 1997 ceasefire called by the Irish Republican Army (IRA) in its campaign against British rule in Northern Ireland.
No one has yet been charged with murder over the Omagh attack, although one man is awaiting trial accused of possessing the timer power unit used to detonate the device.
The only person so far jailed in connection with Omagh, Dundalk publican Colm Murphy, had his conviction quashed by a Dublin appeals court last month and is facing a re-trial.
Relatives of some of the victims are suing five men who they blame for the attack, in a civil action.