A simple but highly sensitive and selective electrochemical sensor for the determination of serotonin (5-HT) was presented. Pretreated glassy carbon electrode (GCE) as enhancer of electron transfer and C-undecylcalix[4]resorcinarene film as molecular receptor are integrated in the electrochemical sensor system. The electrochemical behavior of 5-HT at the modified electrode had been investigated in pH 7.0 phosphate buffers solutions by cyclic voltammetry, square wave voltammetry and chronocoulometry. Compared with bare GCE, the proposed integrated sensor showed improved analytical performance characteristics in catalytic oxidation of 5-HT. Under the selective conditions, the modified electrode showed a linear voltammetric response for the 5-HT within a concentration range of 1.0 x 10(-7) to 1.0 x 10(-5) mol L-1, and a value of 3.0 x 10(-8) mol L-1 was calculated for the detection limit. Besides, due to the difference of potentials, the modified electrode exhibited an excellent immunity from dopamine, epinephrine, ascorbic acid and folic acid interference. (C) 2012 Elsevier Ltd. All rights reserved.