Large groups activities are an undeniable reality of higher education institutions these days. They can be difficult to manage since they imply particular challenges that are not seen in smaller groups of students, however, they allow the development of significant learning experiences. In the research project entitled "What do the best university professors do in large courses? A multi-case study", 50 professors from 8 Chilean universities were identified as the best professors of those institutions. Each one of them was interviewed to identified their perceptions regarding perceived opportunities and challenges when managing large group activities. The results showed that professors identify 5 main challenges: communication, collaborative teacher work, integration of ITCs, promoting peer instruction and peer evaluation, and learning creating environments. In addition, they identify opportunities to improve, such as: student diversity, cooperation, autonomy and proactivity. Important elements that could benefit the educational process.