Abstract: The present invention reveals an apparatus and method for sterilizing instruments at atmospheric pressure in a microwave oven. The apparatus is made of a tray for holding medical, surgical, dental, veterinary, or other instruments, a receiver for holding the tray, three containers, where one container holds a sterilization chemical and a second container holds sterile water, a cover for placement over the tray, and two pumps for transferring the liquids. The method requires a sterilization chemical that has a boiling point of greater than 100.degree. C. and that is at least slightly soluble or is rinsable in water. In addition, the entire microwave sterilization process is completed in less than six minutes.