In this paper I attempt to analyse and survey the role of corrective feedback –more specifically recasts– in the interaction between teachers and L2 students in a classroom. Thus, I explore the effects of recasts on students’ self-correction in order to finally come to the conclusion whether or not students are able to notice this type of underlying correction and, therefore, reformulate their ill-formed utterances. Besides, I also undertake a comprehensive survey of the literature on the topic. Two different groups of students from the English Teaching Trainig Programme at Universidad Católica Raúl Silva Henrríquez are studied. Five students taking English courses at an intermediate level and five taking advanced English courses.Intermediate and advanced students have been categorised on the basis of their number of English language courses they have taken. Intermediate students have taken four, whereas advanced have taken seven. In this paper the point at issue is whether harmful and ineffective or essential and rather effective, and whether recasts are noticeable for students to ‘read between lines’ and figure out the underlying correction. I take the stand that recasts are only effective when using them with advanced students as they are more cognitively advancedand, therefore, able to make inferences and interpret the implicit message to reformulate their mistakes. The results as well as the tests on the whole, clearly demonstrate that recasts  as a corrective technique happen to be a bit more effective with advanced students than with intermediate students, though the difference is not striking.