This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (∼6 times) and the shift in the oxidation potential to lower values (by ∼120mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10M phosphate buffer (pH 7.0) at a fixed potential of 0.65V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20μM, a sensitivity of 241×10 −3 μA/μM, a detection limit of 1.15μM asulam (using the Y B +3σ criterion) and a response time of ∼2s.