Abstract: Background and Objectives: Cr (VI) is identified as one of the toxic heavy metal that is discharged into the environment. Adsorption technique is one of the ideal methods for removal of heavy metals because of its efficiency and low cost. A variety of materials have been tried as adsorbents for removal of Cr (VI). Blue Green Marine Algae (BGMA) is chosen as adsorbent and aimed to investigate its maximum adsorption capacity for adsorption of Cr (VI) from its synthetic stock solutions. Materials and Methods: The metal adsorption capacities of BGMA for adsorption of Cr (VI) ion were studied by varying the initial metal ion concentration from 25-250 ppm. All the experiments were performed at room temperature. To forecast the adsorption isotherms for modeling and to establish the characteristic parameters for process design various models were studied. Results: The optimum pH, biomass loading and an agitation rate for maximum removal of Cr (VI) ion were found to be 5, 2 g and 120 rpm, respectively. Freundlich isotherm was more apt than all other models investigated in this study. Conclusion: L shape of the isotherm indicated that there was no strong competition between solvent and Cr (VI) to occupy the active site s of BGMA. Also it was concluded that BGMA had a limited sorption capacity for adsorption of Cr (VI). Concurrence of Freundlich isotherm with experimental data indicated the extent of heterogeneity of the BGMA surface. The nF value indicated that the adsorption of Cr (VI) from its synthetic solution onto BGMA was favourable one.