Bisphenol A (BPA) has been used worldwide in different industries for production of nursing bottle, food can linings, beverage container. Thus, humans may routinely ingest trace amounts of BPA. Since it is known that BPA is one of the endocrine disrupting compounds (EDCs) its effects on human health have become of growing concern. Therefore, a simple, selective, and sensitive analytical method for the detection of a trace amount of BPA in the environment has become an extremely important issue. To overcome the disadvantages of traditional methods like high performance liquid chromatography (HPLC) or gas chromatography (GC) that rely on costly, sophisticated equipments and time-consuming sample pre-treatment, we developed a highly sensitive, reusable and cost-effective biosensor system. Here, we used aptamers, which are single-stranded oligonucleotides that can bind to their target molecules with high affinity and selectivity, as a recognition element. In this system, the probe-DNA molecule (the complementary sequence of a small part of BAP-aptamer) was covalently immobilized onto the optical fiber sensor surface. Samples containing different concentrations of Bisphenol A were premixed with given concentration of fluorescence-labeled BPA-aptamer, and pumped to the system. Based on the hybridization between fluorescence-labeled-BPA-aptamer and surface immobilized probe-DNA the fluorescent signal is captured by the detector and displayed on the screen straightforwardly. The developed sensing system exhibits a low detection limit of 0.74 ng mL-1, which is much better than the criterion defined by USEPA. æThe biosensors were characterized by good reproducibility, stability of more than 100 assays, and good selectivity for BPA.