Associations of blood PCB concentration with serum levels of triglyceride, gamma-GTP, total-, and conjugated-bilirubin were investigated in "Yusho" patients twenty years after outbreak, using the information obtained from the medical examinations in 1988 and 1989. Study subjects were 259 patients in 1988, and 268 patients in 1989, including 190 patients who consecutively received both examinations. Blood PCB concentrations (mean +/- SE) were 4.78 +/- 0.22 ppb in 1988, and 4.47 +/- 0.17 ppb in 1989. The results of blood-chemical analysis were compared among four categorized concentrations of blood PCB, using the analysis of variance. Significant difference was observed for triglyceride (1988: p < 0.025, 1989: p < 0.005), but not for gamma-GTP, total-, and conjugated-bilirubin. In 1988, the mean triglyceride levels were 108, 137, 145, and 166 mg/dl at < 2.7, > or = 2.7, > or = 4.1, and > or = 6.1 ppb of blood of PCB, respectively. Corresponding figures in 1989 were 106, 129, 154, and 156 mg/dl at < 2.7, > or = 2.7, > or = 4.0, and > or = 5.7 ppb of blood PCB, respectively. Thus, clear positive association between blood PCB and serum triglyceride was observed in the patients twenty years after exposure.