This study was aimed to investigate the effects of environmental pollution with heavy metals from ferro-nickel smelter on Aminolevulinic Acid Dehydratase (ALAD) activity, and to analyze the blood lead level of feral pigeon (Columba livia) in ferro-nickel smelter courtyard in Drenas City, Republic of Kosovo. For this purpose, twenty specimens of feral pigeon (20 birds, males and females), were collected in Drenas city which were living in ferro-nickel smelter courtyard, and 20 specimens in Lubizhdë village as control group (non-contaminated area). ALAD activity in Drenas group was significantly inhibited (P<0.001), compared with ALAD activity of controls. The blood lead level was significantly increased (P=0.015) compared to control group. Correlation between ALAD and blood lead level in Drenas group was negative (r=-0.117; P>0.050) and positive in Lubizhdë group (r=0.452; P> 0.050), but not in significant difference between the input groups. Feral pigeons can play an important role as bioindicators, which can used to monitor the environmental pollution with heavy metals that may originate from Nickel metallurgy. Manuscript profile