Recently, digital radiographic systems are commonly being used in dental faculty hospitals and private clinics. Digital radiography has some advantages when compared to film-based systems, such as; lesser radiation dose, elimination of film processing procedure, image processing options and image archiving. However, the most important disadvantage of the sensors and phosphor plates used in digital intraoral radiography is that they do have high cross contamination risks because they are not disposable like conventional films. To prevent this, intraoral digital sensors are placed into disposable protective covers. Therefore, the aim of this study is to assess in vitro the efficiency of these protective covers used for intraoral phosphor plates in the prevention of microbial contamination.