Batch equilibrium measurements were conducted at 25±2 °C with a granular resorcinol-formaldehyde (RF) resin to determine the distribution coefficients (Kd) for cesium. In the tests, Hanford Site actual waste sample containing radioactive cesium (137Cs) and a pretreated waste sample that was spiked with non-radioactive 133Cs were used. Initial concentrations of non-radioactive cesium in the waste sample were varied to generate an equilibrium isotherm for cesium. Majority of the tests were conducted at 25±2 °C using a liquid to solid phase ratio of 100 ml/g and at a contact time of 72 hours. Two additional tests were conducted at a liquid to solid phase ratio of 10 and at contact time of 120 hours. The measured distribution coefficient (Kd) for radioactive cesium (137Cs) was 948 ml/g, the Kdfor non-radioactive cesium (133Cs) was 1039 ml/g. The Kdfor nonradioactive cesium decreased from 1039 to 691 ml/g with increased initial cesium concentration from 8 to 64 g/ml. Very little change of the Kdwas observed at initial cesium concentration above 64 g/ml. The maximum sorption capacity for cesium on granular RF resin was 1.17 mmole/g dry resin. This value was calculated from the fit of the equilibrium isotherm data to the Dubinin-Radushkevich equation. Previously, a total capacity of 2.84 mmole/g was calculated by Bibler and Wallace for air-dried RF resin.