Anxiety in a large group is a phenomenon much written about, but always as a subjective experience of the therapist and patients. Large group with its regressive situation stimulates the occurrence of archaic defense mechanisms, which gives the leader a special role as one who can influence, with his interventions, the intensity of anxiety. In order to prove the hypothesis of higher anxiety in a large group than in median and small groups, the authors measured the level of anxiety at the beginning and at the end of each of ten consecutive large group sessions.