To investigate the interrelation of heavy metals and the influence on next generation, total mercury and methylmercury, lead, cadmium, manganese, copper, zinc, and iron were determined in the maternal blood, placenta, umbilical cord, and umbilical cord blood. Samples were collected at delivery from 231 pregnant women who were living in the city of Nagoya, located in the central district of Japan, during 1974 and 1978. Total mercury and methylmercury, cadmium, and iron were higher in cord blood than in maternal blood, whereas copper and zinc were lower. Significant positive correlations were observed between maternal and cord blood with regard to total mercury and methylmercury, lead, cadmium, and manganese contents. Significant correlations were also observed between many pairs of metals, particularly in umbilical cord and its blood.