Although the relation between Rapid Automatized Naming (RAN) and Reading is clear, there is no a standardized test to measure the speed of naming in early literacy. The aim is to explore and confirm the factorial structure of the RAN test developed by Wolf and Denkla (2003) in children. RAN test was administred to 442 children aged 4-5 years. Results highlighted two factors: a “nonalphanumeric components” factor which includes “RAN colors” and “RAN images” and an “alphanumeric components” factor which collects “RAN letters” and “ RAN numbers”. Moreover, results highlighted a gradual shift of weight that each component of the test has in the two analyzed years and a consequent reduction in the discrimination ability of the test. In conclusion, this study not only allows to analyze the structure of the instrument “RAN”, but also describes how the speed of naming works over the early literacy.