Ochratoxin A (OTA) is a mycotoxin produced by species of Aspergillus and Penicillium, which contaminates agricultural products that are used in animal feeds. The aim of this study was to measure serum levels of OTA in broiler chickens exposed to different OTA contaminated diets. Seven groups of one-day-old broiler chicks (Cobb) (n=6), were fed OTA contaminated diets at 0.0 (control), 0.1, 0.3, 0.5, 0.7, 0.9 and 1.1 mg/kg feed, for 21 days. On the 21th day, 2 mL of blood were collected from the wing vein, and serum samples obtained by centrifugation. The total amount of consumed feed was determined by daily feed weighing and then average OTA intake of each group was calculated. Serum OTA levels were determined by Competitive Enzyme Linked Immunosorbent Assay (C-ELISA) (n=4), by using anti-OTA monoclonal antibodies. Statistical analysis was performed with ANOVA followed by the Bonferroni test to compare experimental groups to control group. The experiment was conducted in accordance with the legislation and standards of the National Council of Animal Experimentation (CONCEA) and approved by the Ethics Committee on the Use of Animals at the State University of Londrina, PR, Brazil (CEUA 18419.2013.89). Chickens fed OTA contaminated diets had lower feed intake (0.689, 0.652, 0.631, 0.619, 0.597 and 0.564 kg/feed, respectively) than control chickens (0.700 kg/feed) (p<0.05). Estimated OTA intake in contaminated groups was: 0.068, 0.195, 0.315, 0.433, 0.537 and 0.620 mg/OTA, respectively. Serum levels of OTA obtained by C-ELISA were 0.713, 5.721, 4.280, 11.619, 11.819 and 15.266 ng/mL, respectively, in chickens fed OTA contaminated diets, and 0.000 ng/mL in control chickens. It was possible to detect OTA in all groups of chickens fed contaminated OTA diets, but with significant difference in groups that ingested high amounts of OTA (0.7, 0.9 and 1.1 mg/kg feed) in relation to the control group (p<0.01). Based on the estimated OTA intake and C-ELISA results, the average OTA recovery was 2.1%/mL. In conclusion, the higher concentration of OTA in serum agrees with the higher dose of OTA on diets, however the recovery rates of OTA from serum samples are low, suggesting tissue distribution or excess excretion, which requires further studies.