Magnetic and transport properties of the ternary compound Ce3Pd20Si6 are investigated down to 0.035 k. The temperature dependence of the electrical resistivity indicates that this compound is a new Kondo material. The low-temperature specific heat measurement reveals that C/T is strongly enhanced at low temperatures, reaching as high as 8 J/mole Ce·K2 at 0.2 k. This leads to the conclusion that Ce3Pd20Si6 is one of the heaviest-electron systems. © 1995, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.