Studies in Reading Cognitive Psychology area refer to phonological awareness as one of the main predictors of literacy. However, there is no scientific consensus about the size of the phonological unit (e.g., rhymes, alliterations, syllables, phonemes) that most contributes to the initial development of reading and writing skills, considering the languages' regularity degree. In view of this, the present work elaborated, applied and verified the effects of two brief training in phonological awareness, one syllabic and the other phonemic, on emerging literacy skills of Brazilian Portuguese speaking preschoolers. The 64 children that took part in this research were enrolled in the last year of Pre-school, from a public educational institution. The research followed an experimental design, which consisted of the pre-test, intervention and post-test stages, with the participation of a control group. In the pre-test and post-test stages, children were assessed through phonological awareness (PA), knowledge of letters (KL), reading and writing words tasks, as well as an intelligence test. After the pre-test, the participants were randomly divided into three groups, seeking to obtain equivalence between them in relation to the results of the pre-test. The intervention took place in 12 sessions, in the school environment, lasting 30 minutes each, twice a week. The Phonemic Group (PG; n = 21) underwent phonemic awareness training; the Syllabic Group (SG; n = 21), to syllabic awareness training and the Control Group (CG; n = 22) participated in storytelling sessions. Interventions with the PG and SG took place in parallel, in small groups (4 to 6 children) and were carried out by the researcher. At the end of the interventions, all participants went through the post-test, performing again the tests applied in the pre-test (except the intelligence test). The results showed that the children who participated in the interventions in the PG and SG had significantly higher performance than the children in the CG (p <0.05) in the PA skills. In the skills of KL and word reading, the differences were marginally significant (p <0.10) and in the case of writing there was no significant difference between the groups. When the intervention groups (PG x SG) are compared, the results point to the PG's superiority in most of the evaluated skills, with high effect sizes, with the exception of writing. Children will be reassessed soon, already in the 1st year of elementary school, in order to follow up the effects of the interventions.