Twenty male and 20 female agoraphobics, matched for age and marital status, were systematically compared using self-report questionnaire measures of symptoms and hostility, and clinical observations. The males differed significantly from the females as follows: the males were less phobic of social situations but more preoccupied with somatic symptoms and related fears. The females were more phobic of mental illness, more extrapunitive, and reported fewer obsessional symptoms. Two distinct but overlapping clinical sub-groups of males were defined. The sub-group in which separation anxiety, extreme dependence on spouse, denial of hostility and hypochondriasis were prominent, responded poorly to behavioural treatment; the sub-group in which a fear of loss of control of aggressive impulses and generalised anxiety were prominent, responded comparatively well to behaviour therapy.