Ochratoxin A (OTA) is a mycotoxin produced by several species of fungi which commonly contaminates animal feed and food. OTA has been associated to a number of diseases in both animals and humans, predominantly affecting the kidney and has been considered a recognized nephrotoxic agent and a possible carcinogen to humans. In this study, Vero kidney cells were first treated with increasing concentrations of OTA (5–100 μM) for both 24 and 48 h in order to evaluate OTA-induced cytotoxic effects. OTA exposure resulted in a concentration-dependent decrease in cell viability as revealed by the crystal violet and neutral red assays, as well as in an increase in LDH leakage. The cytotoxicity of OTA was also evaluated in the presence of trolox and l-ascorbic acid, two antioxidants with distinct properties. Neither of the antioxidants prevented the cytotoxic effects of OTA in the experimental conditions tested. Moreover, the genotoxicity of OTA in Vero cells was assessed using the cytokinesis-block micronucleus assay. OTA exposure led to concentration-dependent decreases of the nuclear division index (NDI) and of the frequency of binucleated (BN) cells. High concentrations of OTA (50–100 μM) markedly decreased the frequency of BN cells, therefore impairing cell division. Micronuclei (MN) formation was thus assessed for lower OTA concentrations (7.5–25 μM), and revealed significant increases in the frequency of micronucleated BN cells, especially at 25 μM (two-fold increase, p < 0.001). Overall, the results obtained show that OTA is cytotoxic and an effective inducer of MN in Vero cells.