No previous trial has been reported in which only patients with social phobia were treated. There were nine such patients in a previous trial involving 18 agoraphobics and 18 other phobics (Gelder et al, 1973), in which they responded poorly to desensitization but no conclusion could be drawn from such a small sample. Gordon Paul (1966) found that volunteers with public speaking anxiety, a limited manifestation of social phobia, responded better to desensitization than to psychotherapy. Donald Meichenbaum (1971) also showed that similar volunteers responded well to desensitization but when social anxiety was more general subjects did better with a psychotherapy involving modification of self-instructions. It seemed clear that desensitization in the treatment of patients with social anxiety required further investigation and in the present trial it was compared with imaginal implosion and also with social skills training, an in-vivo treatment.