In order to study transfer of n-paraffins in crude oil from fish flesh to animals, following experiment were conducted. n-Paraffins (C(10)-C(20)) were administered orally to rat and distribution of n-paraffins in organs were determined by gas chromatography and the following results were obtained. 1) n-Paraffins were detected in all organs tested. 2) Maximam concentrations of n-paraffins in the organs were in the order of liver adipose tissue femoral muscles blood. 3) n-Paraffins in the organs decreased as the lapse of time relatively fast and the order was liver blood femoral muscles adipose tissue. And adipose tissue were thought to be accumulated tissue of n-paraffins. 4) The concentration of C(16) n-paraffin was the highest in all the n-paraffins and it's biological half life was in the order of blood adipose tissue femoral muscles liver.