A highly sensitive and simple method based on an ionic liquid/ex situ bismuth film-modified single-use pencil graphite electrode (IL/Bi/PGE) was offered for the electrochemical detection of cefixime (CEF) for the first time. The synergistic effects of the ionic liquid and bismuth film combination as the surface modifier remarkably improved the electrochemical response of the modified sensor. Anodic oxidation of CEF was observed at 0.9 V vs. Ag/AgCl/3 M KCl as one well-defined irreversible oxidation peak. Under optimum experimental conditions, the IL/Bi/PGE exhibited a linear relationship for CEF concentrations in the range of 0.005--0.5 $\mu $M (R$^{2}$ = 0.996) with a detection limit as 0.22 nM with square wave voltammetry. The IL/Bi/PGE had excellent sensor properties to electrochemically detect CEF when compared to the literature. This method was successfully applied for practical use with pharmaceutical samples by standard addition method with high accuracy. These results showed that this simple analytical method can find potential application in the clinical field instead of highly expensive and time-consuming processes.