The effect of complexation with yttrium ions and micellar media of surfactants on the fluorescent properties of levofloxacin was studied. The luminescence of levofloxacin depends on the acidity of the medium Т. Г. Данилина и др. Влияние мицелл поверхностно-активных веществ 378 Научный отдел Изв. Сарат. ун-та. Нов. сер. Сер. Химия. Биология. Экология. 2019. Т. 19, вып. 4 and is maximum in an acidic medium. It was shown that complexation with yttrium ions promotes the growth of the intrinsic fluorescence of levofloxacin by a factor of 2. In a weakly alkaline medium, complex formation is accompanied by an increase in intensity of 1.3 times and a bathochromic shift of the absorption band in the spectra of the biologically active ligand. Complexation in micellar media is accompanied by an additional increase in the emission signal by 3 times. The concentration ranges of levofloxacin in which there is a linear dependence on the luminescence intensity of the studied systems are established. The optimal conditions for the maximum fluorescence signal of levofloxacin in aqueous and micellar media of surfactants are found.