This paper discusses the development of both listening and reading skills of two groups of Brazilian secondary students learning English under a task-based thematic syllabus. The data were collected through weekly exchanged lesson diaries, audio- and videotaped sets of lessons, questionnaires, and achievement tests in two moments of the syllabus implementation so that the results could be compared. Aiming at investigating the students' learning gains in both reading and listening comprehension, two next-level groups of Brazilian secondary students were asked to carry out the same achievement tests and their results were compared to the ones achieved by the subjects. The results of this research show that the subjects had learning gains in listening more than in reading.