The present study investigated adsorptive removal of toxic hexavalent chromium Cr(VI) from aqueous solution using manganese dioxide (MnO2). The MnO2 particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDX). Some effective conditions for removal of Cr(VI) using MnO2 were optimized and found to be adsorption time 120 min, adsorbent mass 0.075 g, and pH 4. Under optimum conditions, maximum removal of about 100 % was achieved. Adsortion capacity of Cr(VI) increased with increasing ionic strength while adsorption capacity reached to 72.46 mg/g. Adsorption of Cr(VI) on MnO2 in the absence and in the presence of antibiotic ciprofloxacin (CFX) decreased with increasing ionic strengths and adsorption isotherms fit agreed well with Freundlich model, suggesting that adsorption was mainly governed by electrostatic interaction.