The development of reagents with high affinity and specificity to small molecules is crucial for the high-throughput detection of chemical compounds, such as toxicants or pollutants. Aptamers are short and single-stranded (ss) oligonucleotides able to recognize target molecules with high affinity. Here, we report the selection of ssDNA aptamers that bind to Bisphenol A (BPA), an environmental hormone. Using SELEX process, we isolated high affinity aptamers to BPA from a 10(15) random library of 60 mer ssDNAs. The selected aptamers bound specifically to BPA, but not to structurally similar molecules, such as Bisphenol B with one methyl group difference, or 4,4'-Bisphenol with 2 methyl groups difference. Using these aptamers, we developed an aptamer-based sol-gel biochip and detected BPA dissolved in water. This novel BPA aptamer-based detection can be further applied to the universal and high-specificity detection of small molecules.