The basic structure of plastics (or polymers) is given by macromolecule chains, formulated from monomer units by chemical reactions, such: Poly vinyl chloride (PVC), Vinyl chloride monomer (VCM), Bisphenol A (BPA) and Polypropylene (PP), depending on the type of bonding partners. The aim of the present study was to investigate the effect of plastic on Egyptian workers who had undergone for liver function analysis, (AST and ALT), and (SERPINA1 gene) which provides instructions for making a protein called alpha-1 antitrypsin (A1AT), which is a type of serine protease inhibitor (serpin). One hundred male participants from Qluobiya Governorate were included in this study. They were divided into two groups, 50 healthy participants with no history of plastic exposure (control), and 50 workers occupationally exposed to plastic. Liver functions of both groups (AST & ALT) were determined spectrophotometrically, also liver viruses were analysed for all populations (control and exposer), and the result was negative for all. The two groups were compared as regards to genotype results in a version of the (SERPINA1 gene), they are S and Z allele genotypes that produces alpha-1 antitrypsin using ARMS PCR (Amplification-Refractory Mutation System). The results showed Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST), were significantly (p<0.05) elevated in the exposed group compared to control, and The mean of both AST & ALT were significantly increased (P<0.001) in exposed individuals with MS genotype than control. Heterozygous (MZ), (SZ) and homozygous (SS), (ZZ) genotypes were significantly more frequent in exposed than in controls (P<0.01).