A novel multi-walled carbon nanotube/poly(urea-formaldehyde) (CNT/PUF) composite was prepared for enhanced electrochemical sensing. The composite electrodes were fabricated by the in situ polycondensation of a mixture containing CNTs, and the urea and formaldehyde prepolymer, in electrode tubes with the aid of a curing catalyst. The morphology and structure of the novel composite were investigated by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The results indicate that the CNTs were well dispersed and embedded throughout the PUF matrix to form an interconnected CNT network. The electrocatalytic performance of the CNT/PUF composite electrodes was demonstrated by measuring phenols using cyclic voltammetry and microchip capillary electrophoresis.