The 52-item Illness Behaviour Questionnaire (IBQ) was administered to 134 general practice patients of Greek, Anglo-Greek, and Anglo-Saxon origin. Responses were scored on 7 dimensions of illness behaviour labelled general hypochondriasis, disease conviction, psychological versus somatic perception of illness, affective inhibition, affective disturbance, denial and irritability. Results of a three-way analysis of variance (ethnicity, age and sex) indicated that Greek patients were significantly more likely to differ from their Anglo-Saxon counterparts on the initial 3 IBQ scales. Compared with the Anglo-Saxon group, the Greek sample showed greater hypochrondriacal concern, were more likely to manifest conviction as to the presence of serious physical disease, and took a more somatic view of illness. Anglo-Greek patients varied from one scale to another in the degree to which their responses resembled the pattern of illness behaviour reported by Greek patients. They were most similar to the latter in their hypochondriacal attitude, and least similar in their psychological perception of illness. Although the IBQ responses to the Greek sample were consistent with patterns described in other studies of Mediterranean cultural groups, it was found that relationships observed between ethnicity and illness behaviour were to some extent dependent upon age and sex.