An indirect competitive inhibition type enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of aflatoxin B1, in poultry sera. Preincubation of aflatoxin B1, samples with the antibody prior to competition yielded better results in terms of higher sensitivity. After competition, amount of antibody bound to solid phase was measured by incubation with anti-rabbit immunoglobulins coupled with horse raddish peroxidase. Intensity of colour decreased as the amount of free aflatoxin B1, increased. Final detection of aflatoxin B1, was made by (i) visual comparison with standard aflatoxin B1 using dot-ELISA (qualitative) and (ii) by plate-ELISA, where optical density was measured at 492 nm (quantitative). Plate-ELISA was more sensitive than dot-ELISA, with sensitivity limits being 100 fg and 1 pg per 10 μl, respectively. However, due to ease and speed of performance, dot-ELISA has greater potential as a test for the diagnosis of mycotoxicosis at the field level.