An electroanalytical procedure for the imipramine quantitation in commercial formulation and reconstituted serum was developed in Britton Robinson buffer solution, as supporting electrolyte (0.1 mol L, pH 7.0), with a GPU (graphite-polyurethane composite) electrode and the square wave voltammetry (SWV) technique. The obtained detection limit (LD) and the lower level of quantitation (LLOQ) were 58.3 ng L and 84 μg L, respectively. The procedure is simple, rapid, and precise for the analysis of imipramine in pharmaceutical formulation (98.9±01.3%, 24.7±0.4 mg) without the interference of the excipients. The proposal of direct analysis of imipramine in synthetic serum sample is satisfactory (90.3±3.6%, 22.6±0.9 mg, LD 26.4 μg L, LLOQ 100 μg L), considering the analysis was taken without prior extraction or other sample treatment, which can save costs and reduces the possibility of contamination caused by sample manipulation.