Bisphenol A (BPA) is a xenoestrogen found in the environment, in consequence, for the biosensor detection of BPA we raised antibodies (polyclonal (PAbs) and monoclonal (MAbs)) against a structural analogue of BPA, 4,4 bis-(4-hydroxyphenyl) valeric acid (BVA). The kinetics of the MAb¿BPA interaction were evaluated and the MAb providing the highest affinity was directly immobilized onto the sensor chip surface to evaluate a direct assay. Afterwards, the performance of the MAbs and the PAbs was compared in an inhibition assay using a BVA-coated chip. The highest sensitivity (limit of detection (LOD) of 0.4 ¿g L¿1) was obtained with MAb 12 in the direct assay. However, the inhibition assay was the most robust and the PAbs showed the highest sensitivity (LOD of 0.5¿1 ¿g L¿1). The antibodies were specific for BVA and BPA as only minor cross-reactivities were found toward structurally related compounds or other endocrine disruptors. In the inhibition assay (with a run time of 6 min), water samples spiked with BPA at different levels (0.5¿50 ¿g L¿1) resulted in recoveries varying between 68% and 121%. The sensitivity of the inhibition assay could be improved 40 times (LOD of 0.03 ¿g L¿1 with the Mab 12-based assay) using solid phase extraction (SPE).