Heavy metals are among the most dangerous substances that cause pollution and accumulation in nature. The most bio-sensitive way to decompose these pollutants is through adsorption studies with biopolymers. In this study, chitosan, one of the most common and cost-effective biopolymers, was produced to be employed in adsorption studies of aluminum and lead, which have proven negative effects on living organisms. In the production stages of chitosan, shrimp and crab shells were reduced to three different mesh sizes and deacetylation temperatures of 60, 80 and 100 °C were used. Characterizations of the obtained shrimp and crab based chitosan are made by using Fourier Transform Infrared Spectroscopy and from the results characteristic bands of chitosan are obtained. Adsorption studies were carried out with 20 mg.L-1 heavy metal solutions at different treatment times. According to the results of the adsorption studies determined by ICP–OES analysis, for shrimp and crab based products respectively, aluminum was adsorbed between 58.45% – 99.50% and 23.75% – 83.10%, and lead was adsorbed between 99.35% – 100%, and 72.80% – 92.00%.