Hand Sanitizer Vs Hand Washing

According to research performed by the U.S. Centers for Disease Control and Prevention, hand sanitizer is considered as effective at killing germs as washing your hands with soap and water, unless hands are visibly soiled.

The main point to remember, however, is that the alcohol content of the handrub must be at least 60 percent to be effective.

From here:
http://coldflu.about.com/od/prevention/qt/handsanitizer.htm