The main reason not to hire overqualified candidates is that the minute a better, higher paying job in their area of expertise is offered, they are gone. That's exactly why college graduates find it difficult to get hired into non-management, entry-level positions at places such as Wal-Mart and McDonalds. You invest in a new employee with uniforms and training and are too oftenrewarded with a two-week notice. If you need a ditch digger, hire the best, most experienced ditch digger you can find. DON'T hire the guy who designed the backhoe he'll be using. He won't be around long.