The toxic metals biomonitoring of the environment around the metallurgical complex of "Trepça" in Mitrovica, Kosovo were realised. Our investigation has taken place in Mitrovica (area with heavy metal pollution) and Vernica; Vushtrri (control group), 25 km far from the contaminated area. For this purpose, we have analyzed 22 samples of Roman snails (Helix pomatia) in each area to determine the amount of total proteins (TP) in the hemolymph and hepatopancreas; heavy metals (Pb, Cd, Cu, Zn) concentration and the activity of delta-aminolevulinic acid dehydratase enzyme (ALAD) in hepatopancreas. Our results show a significantly lower amount of total proteins in the Mitrovica (Mitrovica:16.16±2.419; Vernica:17.9±9.22; P< 0.013). The concentration of metals (Mitrovica: Pb=37.6 ± 2.1, Cd=605.2 ± 308, Zn=51.7 ± 27.8 and Cu=8.5 ± 6.3; Vernica: Pb = 3.7 ± 3.8, Cd=49.22 ± 25.7, Zn=3.9 ± 2.8 and Cu=7.3 ± 6.8) were significantly higher (P < 0.001). We found out the significantly positive correlation between all metals in the study: Pb/Cd (r=0.572; P<0.005); Pb/Cu (r=0.758; P<0.001); Pb/Zn (r=0.857; P<0.001); Cd/Cu (r=0.693; P<0.001); Cd/Zn (r=1.00; P<0.001); Cu/Zn (r=0.685; P<0.001). The activity of ALAD was significantly inhibited (Mitrovica=3.25 ± 1.25; Vernica=6.4 ± 2.3; P<0.001) and the correlation between ALAD and Pb was significantly negative (r=-0.472; P=0.026). The polluted environment with heavy metals in Mitrovica (mostly with the Pb and Cd) harms the biochemistry of Roman snail. This animal species may be used as a good animal model to monitor environmental pollution with heavy metals.