This Intervention Project explores the impact of Cooperative-group activities conducted on ESP students and their metacognition and reflection on them. By means of this Project the aim is to acquire a better teaching performance as well as to reflect upon the daily practice of language teaching and to improve learners’ performance on ESP activities. Research carried out by Burke (2011), clearly identifies a students’ tendency to dislike Cooperative activities in class, which impedes them from learning and acquiring language appropriately, gaining leadership skills or team work organization. This project first relied on an initial survey to identify the existence of such a problem in the ESP class, confirming that more than 80% of the students actually had Cooperative learning difficulties. Given this scenario, two interventions were carried out. In the intervention activities, the students had to work exclusively on Cooperative-based learning activities. After these interventions, qualitative data collection in the form of interviews was carried out. Analysis led to conclude that the tasks had a positive impact on learning, leading to success.