The electrochemical oxidation of 2,6-diaminopurine (2,6-DAP) was studied in pH 7.4 phosphate buffer solution on multiwall carbon nanotube modified glassy carbon electrode (MWCNT/GCE) over a temperature range of 20 to 50 degrees C using cyclic voltammetry. 2,6-DAP oxidation on MWCNT/GCE showed a well-defined and irreversible oxidation peak at about 0.72 V vs. Ag/AgCl at pH 7.4. The oxidation potential of 2,6-DAP linearly varied with pH over the range of 3.0 to 10.0 with a slope of -0.0547 V/pH, implying that 2 protons were accompanied by 2 electrons transferred in the electrochemical reaction. The activation energy, Ea, of oxidation reaction was found to be 33.10 +/- 1.88 kJ/mol. The differential pulse voltammetric determination of 2,6-DAP was also studied. The peak currents increased linearly with increasing of the 2,6-DAP concentration range from 0.4 mu mol/L to 80 mu mol/L. The linear regression equation appeared as I-p/mu A = -(1.66 +/- 0.42) + (4.21 +/- 0.11) [2,6-DAP]/mu mol/L, R-2 = 0.9982, and the detection limit (S/N = 3) was 3 x 10(-7) +/- 0.015 mol/L (n = 3). The electrocatalytic oxidation of 2,6-DAP on MWCNT/GCE showed that acid pretreated multiwall carbon nanotube can be used in new applications in electrochemical determinations of biologically important compounds.