The potentiometric measurements for the interaction of sparfloxacin (SPFX) and metal ions Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with nucleosides (NS) adenosine, guanosine, cytidine and inosine were studied. The formation of various 1:1:1 ternary complex species are inferred from the potentiometric pH titration curves. The experimental conditions were selected such that self-association of the nucleosides and their complexes due to stacking interaction was negligibly small; that is the protonated ternary complexes, were studied. The formation of ternary complexes of some systems was confirmed by UV-Visible measurements in solution.