The adsorption of a series of Astrazone cationic dyes and methylene blue on the moss, Calymperes delessertii Besch, was studied. The results indicate that Langmuir isotherm can be successfully applied, and adsorption of these dyes on the moss is a feasible process. A series of fixed bed experiments was undertaken and the results were compared with the bed depth service time model for adsorption columns.