Abstract: Based on the sensitizing action of Zn2+ on the fluorescence emission of the reaction system of levofloxacin (LVFX) and quantum dots of CdS in a B-R buffer solution of pH 2.55, a fluorophotometric method for determination of LVFX was proposed. Linear relationship was found between values of fluorescence intensity and mass concentration of LVFX in the range of 1-40 mg·L-1 as measured at wavelengths of 370 nm (λex) and 508 nm (λem). Detection limit (3S/N) found was 0.11 mg·L-1. The proposed method was applied to the determination of LVFX in samples of tablets and capsules, giving results in consistency with those obtained by HPLC. Values of RSD (n=5) found were less than 3%.