Microplastic materials include plastic particles smaller than 5 mm that have been identified as one of the main pollutants, especially in the marine environment. This thesis provides data of the presence of microplastics in the sediments of the Italian shelf. A total of four sediment cores were analysed, two sampled in the area of the shelf of the southern coast of Sicily, and two in the area of the shelf of the Tuscan Islands. The sediments were weighed and sieved, and the microplastic was successfully separated from the sediment by density separation method using sodium polytungstat (SPT) solution. Physical and chemical characterization of plastic particles was performed with regard to shape, color, and type of polymer. Fragments are the most common shape category of microplastics in all analyzed locations, while fibers represent the rest of the shapes found. The main color of fragments was grey, while the fibers were mostly light colored. The type of polymer was analyzed using the ATR (Attenuated total reflection) method on FTIR (Fourier-transform infrared spectroscopy) which shows that the largest number of particles belongs to polyvinyl chloride (PVC), followed by ethylene-vinyl acetate (EVA). Microplastic particles for which the type of polymer could not be determined were mainly recorded using the KBr tablet method, which can be ruled out as a method for microplastic analysis without additional modifications.