Electrochemical measurement of salicylate was performed using recombinant Escherichia coli cells immobilized in polyvinyl alcohol (PVA) beads. Among aromatic hydrocarbons, salicylate is chosen as a model compound because it is less toxic than other aromatic hydrocarbons and soluble in water. Recombinant E. coli cells carrying nahR (encoding the NahR regulatory protein for naphthalene and salicylate degradation)::lacZ fusion genes were constructed, immobilized in PVA beads and induced with salicylate, and their biosensing activities were electrochemically monitored using p-aminophenyl-β-d-galactopyranoside (PAPG) as the enzymatic substrate. The redox response of p-aminophenol (PAP), a catabolite of PAPG, was measured by either cyclic voltammetry (as the peak current) or chronoamperometry (as the steady-state current). Various paramete; 4.5%; n = 5), and the system showed good stability, with 80–100% activity remaining after 7 h of operation or 2 weeks of storage at 4 ℃. This system has advantages over existing optical techniques, including better speed and a lower detection limit.