Kizilirmak is the longest river in Turkey. One of Turkey's largest petroleum refineries is located fairly nearby the river and, hence it is the main source of its metal pollution. The present study was carried out to evaluate the protective role of lycopene on refinery wastewater-induced cytotoxicity in maize root tip cells. We used the germination percentage, root length, weight gain and micronucleus (MN) frequency as indicators of cytotoxicity. Additionally to the cytological analysis, lipid peroxidation and DNA analyses were performed in the root tips of the maize seeds.