The present work aims to investigate the removal of three cationic dyes (Basic Orange 2, Basic Yellow 2 and Basic Violet 3) from aqueous solutions by montmorillonite under various experimental conditions. Cationic dyes were selected Basic Orange 2 (BO2), Basic Yellow 2 (BY2) and Basic Violet 3 (BV3). The effects of pH, initial dye concentration, adsorbent dose, agitation speed and ionic strength, on the removal of dyes were studied. According to the experiments results, it was shown, that maximum removal was achieved in less than 45 min. The results indicate that the montmorillonite can be used as a low cost alternative according to other adsorbents in the removal of dyes from wastewater. The maximum adsorption efficiency levels attained were as follows: 95.849% BO2, 99.562% BY2 and 99.169% BV3 onto montmorillonite at pH: 5.0, 100 mg/L initial dye concentration, 0.75g/L clay dosage, 300 rpm agitation speed, 0 M NaCl ionic strength and 293 K, reaction time of 45 min.