If it's a federal job -- you *could* be charged with lying. Though it's rare. It'll probably prevent you from getting any other gov't job or security clearance.
For a corporate job -- it'll just mean you don't get it. Which you probably wouldn't have -- if they had found out about it (i assume it's a crime that even if you were upfront about it -- you probably wouldn't get it).
Personally -- I don't believe in Companies violating your privacy by asking personal questions of the sort. Arrest records are public records, so they're more than welcome to search it themselves. Then again, i work in more "high-level" type jobs, where you rarely if ever find ex-druggies, gang-members, felons, murderers, rapists, etc. running around in my field. So it's really a non-issue.
But if it's some trivial charges -- just admit it. You'll quickly find out just how "important" you are to their organization and how much they value your services if they start to raise a stink about it. It'll probably speak volumes about their "culture" giving you a chance to also mull on whether you wish to join them, if that culture seems very heavy-handed and militaristic.