A promising electrochemical sensor was developed based on a layer by layer process by electropolymerization of pyrrole in the presence of new coccine (NC) as dopant anion on the surface of the multi-walled carbon nanotubes (MWCNTs) pre-coated glassy carbon electrode (GCE). The modified electrode was used as a new and sensitive electrochemical sensor for voltammetric determination of sumatriptan (SUM). The electrochemical behavior of SUM was investigated on the surface of the modified electrode using linear sweep voltammetry (LSV). The results showed a remarkable increase (similar to 12 times) in the anodic peak current of SUM in comparison to the bare GCE. The effect of experimental variables such as, drop size of the casted MWCNTs suspension, pH of the supporting electrolyte, accumulation conditions and the number of cycles in the electro-polymerization process on the electrode response was investigated. Under the optimum conditions, the modified electrode showed a wide linear dynamic range of 0.02-10.0 mu mol L-1 with a detection limit of 6 nmol L-1 for the voltammetric determination of SUM. The prepared electrode showed high sensitivity, stability and good reproducibility in response to SUM. This sensor was successfully applied for the accurate determination of trace amounts of SUM in pharmaceutical and clinical preparations. (C) 2011 Elsevier Ltd. All rights reserved.