The present questionnaire-based study examines the views of 428 Greek students (aged 13-18 years) from 30 secondary education schools in Athens, who have experienced cooperative learning in group work--an instructional learning strategy not often implemented in Greek schools. The research focuses on students' preferences as regards the composition of their group and the distribution of roles and tasks within it, and finally the evaluation of and the reward for personal and group performance. Data elaboration, statistical and factor analysis showed that students participate more willingly in group work when wider autonomy is provided and their friends participate in the group, although new friendly relationships with the other members are not developed. It also showed that Greek students prefer clearly defined tasks, seek mainly cognitive attainments, want to be assessed on the basis of socio-affective skills development, dislike grade rewards for group work attainments and prefer non-grade rewards such as praise, provision of free time and excursions. (Contains 4 tables and 1 figure.)