The pi-A isotherms and UV-vis spectra of the transferred films suggested that the monolayer of p-tertbutylthiacalix[4]arene can coordinate with Ag+ at the air-water surface. From these observations, a glassy carbon electrode coated with Langmuir-Blodgett film of p-tert-butylthiacalix[4]arene is designed for the determination of trace amounts of Ag+. Compared with bare glassy carbon electrode and modified glassy carbon electrode using direct coating method, the Langmuir-Blodgett film modified electrode can greatly improve the measuring sensitivity of Ag+. Under the optimum experimental conditions, the Langmuir-Blodgett film modified electrode in 0.1 mol L-1 HNO3 shows a linear voltammetric response in the range of 5.0 x 10(-9)-2.0 x 10(-6) mol L-1 with detection limit 3.0 x 10(-9) mol L-1 for Ag+. The high sensitivity, selectivity, and stability of this Langmuir-Blodgett film modified electrode also demonstrate its practical application for a simple, rapid and economical determination of Ag+ in water sample. (C) 2009 Elsevier B.V. All rights reserved.