In the present study, an antihistamine drug, cetirizine hydrochloride (CTZN), was determined using square wave voltammetry and cyclic voltammetry based on its oxidation in a disposable and unmodified/bare graphite pencil electrode. To see the electrochemical behavior of CTZN, cyclic voltammograms of 0.10 mM CTZN in various types of carbon-based electrodes such as glassy carbon electrode (GCE), carbon paste electrode, multi-walled carbon nanotube (MWCNT) modified GCE, graphite pencil(GP), and pretreated graphite pencil (p.GP) were recorded in pH 3.0 Britton Robinson Buffer (BRB) solution. The result showed that CTZN is irreversibly oxidized at around + 1.0 V in all electrodes and among the studied electrodes p.GP showed the highest oxidation current for CTZN. Thus, the effect of pH on the electrochemical response of CTZN was investigated at the p.GP electrode by recording cyclic voltammograms of 0.10 mM CTZN in the BRB solutions in which pH was ranging from 2.0 to 10.0. The highest oxidation current of CTZN was observed at pH 2.0 BRB solution. Under the optimized SW voltammetric conditions, a linear response for the determination of CTZN was obtained in the range from 0.50 to 10.0 mu M CTZN with a detection limit (LOD) of 0.16 mu M. Applicability of the proposed sensor was also tested for determination of CTZN in antihistamine syrup (Zyrtec). Results of the measurements indicated that p.GP can be successfully used for CTZN detection in real samples.