Teaching in groups is the organizational form of teaching. Students are divided into several groups and they cooperate to solve certain task. Mutual help and involvement of passive and diffident student is a big advantage. This form of teaching has disadvantages and several problems too. Teacher should arrange and prepare everything carefully. Teacher's role is different in this type of teaching. When teacher is planning, he should realize what he wants to achieve, how large groups will be appropriate, how to divide students into groups etc. Classical arrangement of class for frontal teaching is inappropriate for teaching in groups. In this form of teaching students should see each other. All groups can do the same work or each group can do a different work. Student assessment is a problem in this way of teaching too. Some teachers can not cope with this. Teaching in groups may not be always cooperative. Key words: activating form of teaching, teaching in groups, cooperative teaching, teaching in pair, heterogeneous group, homogeneous group, role in the group, cooperative skills