Autopsy findings of 12 patients with yusho including 2 stillborn babies are reported. Characteristic pathological changes were acne-like eruptions and cutaneous pigmentation with histological features of follicular hyperkeratosis, dilated hair follicles, and an increase of melanin pigment of the epidermis. In addition to the skin lesions, multiplication of the duct epithelium of the esophageal gland was found in 6 patients. Unusual multiple small foci of myocardial necrosis and fibrosis with basophilic myofibrillar degeneration were found in one patient, suggesting a relation to PCB exposure. Five cases with carcinomas (two involving the liver, two the lung, and one the esophagus) were also found, but their causal relationship with PCB was not certain. Nine cases showed the characteristic gas chromatographic pattern of yusho, but two cases had the same one as that of healthy controls.