It is said that itai-itai disease is a Fanconi syndrome caused by chronic cadmium poisoning. No clear conclusion has been reached as yet concerning the reason why many cases of this disease were found among aged muliparae, and almost no cases were found among males. The authors have previously reported that an early diagnosis and a differential diagnosis of itai-itai disease were possible by comparing urine gel filtration patterns, and that a presumption of the degree of kidney disorder by the G25 albumin ratio was possible. It was also found that the G25 albumin ratio could be used as an indication of the degree of kidney disorder caused by chronic cadmium poisoning. Therefore, the gel filtration patterns of urine, the G25 albumin ratio of inhabitants in the area of itai-itai disease incidence, and the life history of patients were studied. Cases of kidney disorder caused by chronic cadmium poisoning were found in both sexes. The authors have the opinion that itai-itai disease was possibly caused by intake of cadmium in great quantities, especially during the period of pregnancy.