The adsorption of Cr(III) was studied at pH 1, 2, 3, 4, 6, 8, and 10 on chlorite and kaolinite and at pH l, 2, 3, and 6 on illite. The amount of chromium adsorbed on chlorite varied from 3.1 l0 -5 mole/ g at pH 1 to 16.6 10 -3 mole/g at pH 4, and on illite from 4.9 10 -5 mole/g to 9.2 10 5 mole/g at pH 1 and 3, respectively. Kaolinite adsorbed 3.7 10 -5 mole Cr/g at pH 1, 2, and 3 and 5.5 10 -5 mole Cr/ g at pH 4. Measurements of the Cr 2p core-level binding energies indicate that chromium is probably ad- sorbed as a Cr(III) aqua ion at pH values below 4. The binding energies for the Cr 2p level for samples prepared above pH 4 compare favorably with the value determined for chromium hydroxide and lead to the conclusion that the chromium species present at pH 6, 8, and l0 is chromium hydroxide.