[en] This paper presents a study on the batch adsorption of crystal violet dye from aqueous solution onto Posidonia oceanica L. fibers in order to explore their potential use as low cost adsorbents for wastewater dye removal. A series of batch tests were conducted and the influence of contact time, initial dye concentration, pH of the solution and adsorbent dosage on crystal violet removal was investigated. FT-IR spectroscopy analysis of the Posidonia oceanica L. fibers before and after dye sorption was also investigated to confirm the mechanism of the removal of crystal violet. Results indicate that crystal violet uptake increased with increased initial dye concentration and decreased with increased pH values. The results showed that the highest dye adsorption capacity (11.75 mg/g) was found at pH = 6, for an adsorbent dosage of 5 g/L, initial dye concentration of 60 mg/L, under a constant temperature of 23±02 degree, and the equilibrium state was reached within 10 min of exposure time. The relatively low cost and high capabilities of Posidonia oceanica L. fibers make them potentially attractive options for dye removal from dilute industrial effluents.