Considering the importance of oral language to ulterior literacy, this research analyzed the relationships between oral language abilities, assessed in preschool level, and reading competence, assessed in the first grade. Twenty-seven children, with five years old at the beginning of the study, were assessed in preschool level with Phonological Awareness Test (PAT), Syntactic Awareness Test, Phonological Discrimination Test, Pseudowords and Words Repetition Test (PWRT), Naming Test, Letters Knowledge Test (LKT) and Peabody Picture Vocabulary Test; and they were assessed in the first grade with Pseudowords and Words Reading Competence Test. The regression analyses showed that the abilities evaluated by the PAT, LKT and PWRT exercised significant effect over the reading competence evaluated a year afterwards, corroborating the relations between oral language abilities and reading, and aim for the phonological awareness as the best predictor of success in the written language acquisition.