The ability of Annona muricata L. seeds to adsorp Rhodamine B from aqueous solution was studied using batch method. Seed was activated using HCL 0.01 mol/L . The experiment result found that the optimum condition achieved at pH 4, initial concentration of Rhodamine B 500 mg/L, biosorbent doze 0.05 g, agitation rate 100 rpm, contact time 180 second and biosorbent temperature at 70oC. Biosorption capacity at optimum condition is 53.376 mg/g. The adsorption isotherms data was analyzed using the Langmuir and Freundlich. Langmuir Isotherms has higher R2 value with 0.9009 and 0.8063 for Freundlich Isotherm. Langmuir Isotherm indicate that the process happen in adsorption was chemisorption.