A traveler was surprised recently when he was denied entry from the United States into Canada. The reason: Four years ago, he was convicted in the United States of driving under the influence of alcohol.

“I was put on the next plane back home. Sad, humiliating, and I think ridiculous,” says the man, who asked that his name not be used.

Actually, most countries bar foreign visitors with criminal records for some period of time. But each country has widely differing rules on what qualifies as a serious enough infraction to bar the door.

Canada’s rules generally apply to any indictable criminal offense, including drunken driving and shoplifting – offenses they can find on various criminal databases. Last year, Canadian officials refused admittance to 17,841 foreign visitors because of their criminal records, said immigration spokesman Jean-Pierre Morin.

But he adds that his country allows for rehabilitation. A foreign national with a single offense is deemed rehabilitated after 10 years. If at least five years have passed since your crime, you might be able to apply for rehabilitation by filling out a form; decisions are made on a case-by-case basis at the Canadian consulate. Details: www.cic.gc.ca.