Transfer of radioactive silver has been studied quantitatively in sliding contacts containing graphite and metal. The rate of transfer from silver-graphite riders to graphite cylinders is initially high but soon approaches a limiting equilibrium state. The amount of silver transfer increases markedly with surface roughness. Further, the transfer is enhanced by the addition of liquid water to the rider track. Back transfer to the rider has been found to consist mostly of loosely clinging dust in the rider face. Silver transfer to a copper cylinder is much greater than to a graphite cylinder, the difference being roughly twenty-fold. Within the experimental conditions, the transfer/unit time to both graphite and copper cylinders is greater at 1 cm/sec than at 390 cm/sec.