In this study, the adsorption efficiency of Ethiopian sodium bentonite clay adsorbent for removal of Cr (III) and Cr (VI) ions from tannery effluents has been investigated. The clay was found from Gewane area, Afar region, Northeastern Ethiopia and taken from Ethiopian Mineral, Petroleum and Biofuel Corporation in Addis Ababa. The raw clay was characterized by FT-IR Spectroscopy and XRD to identify the functional groups (different Si-bonds and –OH groups on the surfaces of bentonite) and crystalline structure (predominantly montmorillonite clay family) respectively. The X-ray analysis diffractometric of Na-bentonite shows that there was a majority phase of montmorillonite, and minority phases of feldspar and quartz in the clay. The adsorption of the chromium ions on sodium bentonite was investigated during a series of batch adsorption experiments carried out to determine the effect of different parameters like contact time, initial chromium ion concentration, pH and temperature for the maximum removal of chromium. A maximum chromium adsorption of 98.48% (Cr+3) and 95.20% (Cr+6) was achieved at pH 4, initial chromium concentration of 25 mg/l, contact time of 120 minutes and temperature of 40 °c. The adsorption process has fit Langmuir isotherm model.