The relationship between contents of schizophrenic delusions and sociocultural background in the modern society of Japan and China were studied from transcultural psychiatric aspects. The data of this study were derived from the public mental hospitals in Tokyo and Shanghai in a similar size; of 186 cases (88 cases of male, 98 cases of female) of the first admission in Tokyo Metropolitan Matsuzawa Hospital during 1981-1983, 112 cases with delusions (53 cases of male, 59 cases of female) were selected, and of 200 cases (112 cases of male, 88 cases of female) of the first admission in Shanghai Psychiatric Hospital in 1983, 129 cases with delusions (70 cases of male, 59 cases of female) were chosen. The incidence of delusions of physical persecution and grandeur was relatively high in patients of both hospitals in Tokyo and Shanghai, while the incidence of delusions with hypochondria and guilt was low in both hospitals. Only the incidence of delusion of poisoning was significantly higher in Shanghai than in Tokyo (mean 2 = 12.97, p less than 0.001). After the World War II, the patriarchally oriented family system was abolished in Japan which caused shifting the system from a large family to a nuclear family. In China where the property (land) and daily life were closely connected the close human relationship among generations had important values in relation to the labor power within the frame of a large family. It is believed that occurrence of the delusion of poisoning might be a reflection of the disturbed human relationship within the family member in dining which should be helpful for making further understanding and reliance. It's occurrence conflict and struggle in the community of the outside of the family. At present there is a marked difference between Chinese and Japanese in their structure of consciousness. The former places high value and meaningfulness on the participation to the group and seeks protection and safety of individuals. The latter reveals a less strong tie with the traditional conformity and dependency to the mass due to the conformation of the nuclear family. It can not be ignored the possible effect of the close horizontal interaction and cautious human relationships among neighbours with fear of rumor and watching in the Chinese community on the occurrence of the delusion of persecution. After the World War II, abolishment of the principle of vertical control system and introduction of multiple value system together with loss of authority had taken place in Japan.(ABSTRACT TRUNCATED AT 400 WORDS)