In the present investigation, the adsorption of arsenic in chitosan, which was obtained from shrimp, was evaluated. The optimal conditions (chitosan concentration, particle size, temperature and contact time) for the adsorption process of arsenic ions present in an artificial solution were determined, which allowed determining the arsenic concentration in different stages of chitosan adsorption, and in this way, it was possible to obtain the kinetic behavior of the arsenic adsorption process on the polymer under study. It was determined that chitosan is a good adsorbent for arsenic ions, obtaining an adsorption of 92.74%. The influence of the chitosan granulometry in the process was not significant since when working with 200 mesh a value of 92.74% of arsenic adsorption in chitosan was reported and without grinding the chitosan the result obtained was 87.46%. Regarding the working temperature, it can be determined that this does have a great influence on the adsorption process, it could be concluded that at a temperature of 20ºC, better recovery ranges for arsenic ions were obtained, which was also determined in the reaction kinetics.