The ministry first reported the arrest of eight men, said to be linked to al Qaeda and allegedly planning to attack oil installations in the kingdom.
An interior ministry statement, carried by the Saudi Press Agency, said the eight were part of a terrorist cell led by a non-Saudi man, who was one of the arrested. The planned attacks were to take place in the eastern region of the country, which is home to Saudi's main oil resources.
The arrest of the eight "pre-empted an imminent attack on an oil installation," the statement said without naming the target or providing more details.
The ministry also said 22 other suspects were arrested for allegedly supporting the al Qaeda terror network. This group plotted to assassinate the country's religious leaders and security officials, it said.
Eighteen others, led by an alleged expert in launching missiles, were arrested separately.
"They were planning to smuggle eight missiles into the kingdom to carry out terrorist operations," the ministry's statement said of that group.
Also, 112 other Saudis were taken into custody for links and "coordination with outside circles" to assist in smuggling men to troubled areas - shorthand for Iraq and Afghanistan - for training, after which they would be brought back for attacks in the kingdom, the statement added.
Thirty-two more men were arrested, both Saudis and non-Saudi, for providing financial aid to al Qaeda operations here, the ministry said.
Sixteen men were also arrested in the holy city of Medina for colluding to issue a publication propagating "misleading ideology" and criminal acts, the ministry said. The group also worked on helping volunteers go fight in Afghanistan and Iraq.
The Wednesday announcement gave no timeline on the arrests of the separate groups.
The total number of the arrested was 208.
Saudi Arabia, which has a quarter of the world's proven oil reserves, has seen a rise in attacks by Islamist extremists over the last few years.
The kingdom, which is the birth place of al Qaeda leader Osama bin Laden, has been waging a heavy crackdown on al Qaeda militants since a wave of attacks on foreigners in the kingdom in 2003.
In February 2006, two suicide bombers attacked the oil facility at Abqaiq on the east coast, killing two security guards and wounding eight foreign workers in an incident later claimed by the Saudi branch of al Qaeda.
The previous large sweep by the Saudi authorities was announced in April, netting 172 militants, including pilots they say were trained for oil refinery attacks using civilian planes.
In August, Saudi Arabia said it was setting up a 35,000-strong special force to protect its oil facilities due to the increasing threats against al Qaeda.