In this paper, a mercury-free and modification-free electroanalytical methodology based on anodically pretreated boron-doped diamond electrode is described for the quantification of enrofloxacin. The oxidation of compound was irreversible and presented an adsorption controlled process. The sensitivity of the stripping voltammetric measurements was significantly improved when the anionic surfactant, sodium dodecylsulfate (SDS) was present in the electrolyte solution. Using square-wave stripping mode, a linear response was obtained for enrofloxacin determination in 0.1 mol L-1 HNO3 solution containing 9 x 10(-4) mol L-1 SDS at +1.27 V (vs. Ag/AgCl) (after 60 s accumulation at open-circuit condition). Linearity was found within 0.025 to 1.0 mu g mL(-1) (6.96 x 10(-8)-2.78 x 10(-6) mol L-1) with a detection limit 0.0057 mu g mL(-1) (1.59 x 10(-8) mol L-1). The proposed method could be used for the determination of enrofloxacin in pharmaceutical formulations and the spiked human urine samples with acceptable recoveries.