Avidin-modified polyaniline (PANI) electrochemically deposited onto a Pt disk electrode has been utilized for direct detection of Escherichia coli by immobilizing a 5'-biotin-labeled E. coli probe (BdE) using a differential pulse voltammetric technique in the presence of methylene blue as a DNA hybridization indicator. Depending on the target sample and the sonication time, this BdE-avidin-PANI bioelectrode can be utilized to electrochemically detect a complementary target probe (0.009 ng/microL), E. coli genomic DNA (0.01 ng/microL) and 11 E. coli cells/mL in 60 s to 14 min (hybridization time) without using PCR and can be used 5-7 times at temperatures of 30-45 degrees C.