Silver nanoparticles (size: $7.9{pm}0.95$ nm, dosage: 250 mg/kg) were orally administered to pregnant rats. At 4 days after parturition, four pups were randomly selected (one pup from one dam) and silver level in liver, kidney, lung and brain was determined by ICP-MS and electron microscope. As results, silver nanoparticles highly accumulated in the tissues of the pups. Silver level in the treated group was $132.4{pm}43.9$ ng/g in the kidney (12.3 fold compared to control group), $37.3{pm}11.3$ ng/g in the liver (7.9 fold), $42.0{pm}8.6$ ng/g in the lung (5.9 fold), and $31.1{pm}4.3$ ng/g in the brain (5.4 fold). This result suggested that the possible transfer of silver nanoparticles from pregnant dams to the fetus through mainly placenta.