The analytical potential of a boron-doped diamond electrode (BDD) and square-wave voltammetry (SWV) for the determination of rosuvastatin calcium (ROS) was investigated. The voltammetric response of the ROS molecule was evaluated with a BDD electrode that was subjected to anodic (positive polarization, +3.0V for 5.0s) or cathodic (negative polarization, −3.0V for 15.0s) pretreatments. The target analyte showed an irreversible anodic process at ≈1.4V (vs. Ag/AgCl (3.0molL−1 KCl)) with an enhanced current response at a BDD electrode that was cathodically pretreated. Using the cathodically pretreated BDD electrode, other experimental conditions were optimized, including the supporting electrolyte and SWV parameters. Under optimized experimental conditions, the analytical curve was linear in the ROS concentration from 9.40 to 88.8mgL−1 (9.40 to 88.8μmolL−1), with a correlation coefficient of 0.998 and limit of detection of 1.04mgL−1 (1.04μmolL−1). The proposed method was successfully applied for ROS determination in pharmaceutical formulations and the electrochemically determined quantity of drug was in close agreement with the results obtained using a spectrophotometric method at the 95% confidence level. Additionally, biological fluid samples of urine and human serum were directly analyzed by the proposed voltammetric procedure, with excellent results of recovery.