The corn rootworm (Diabrotica virgifera virgifera LeConte) is one of the most important and dangerous pests of corn. It has one generation per year and three developmental stages. The larva feeds on the roots of plants and the adult form feeds on the aerial parts of plants, damaging them. The greatest damage caused by the larvae is manifested in the fact that the plants easily lie down if they have damaged roots and damage to the roots leads to a reduced yield. However, in addition to direct damage, corn rootworm can be a carrier of mycotoxigenic fungi and thus contribute to the contamination of corn. Mycotoxins are secondary metabolites of fungi that can have a toxic effect on humans and animals. Factors that affect the emergence and formation of mycotoxins are temperature, moisture, insects present in the field or some mechanical damage to plant organs. Some of the most economically significant mycotoxins are aflatoxin B1 and ochratoxin A. The research was carried out as part of the project "Production of food, biocomposites and biofuels from cereals in a circular economy" (EFRR) (projekt-klima.eu)., KK 05.1.1.02.0016, financed by the Ministry of the Environment of the Republic of Croatia from ESF funds, Operational Program Competitiveness and Cohesion. For the purpose of this research, adult forms of the corn rootworms were collected. A total of 100 samples were collected by visual inspection of plants. There were 60 potential samples for aflatoxin B1 and 60 potential samples for ochratoxin A determined. Out of 179 pure cultures, the number of producers of aflatoxin B1 was 2.8% and the total number of producers of ochratoxin A was 3.4%. The samples that were positive for aflatoxin B1 and ochratoxin A belong to the genera Aspergillus and Penicillium.