A number of successful applications have been found that use cyclodextrin complexation ability. In the present work we analyse β-cyclodextrin (β-CD) complexes with 2Ј,3Ј-dideoxynucleosides (ddA, ddG, ddI) exhibiting high antiviral activity against HIV strains. The formation of the complexes has been analysed by 1 H NMR-monitored titration. On the basis of concentration dependencies of proton chemical shifts, the nucleosides in this study form complexes of 1 : 1 stoichiometry with β-CD. The bonding constants depend on ligand type and could be estimated as 35 ± 10 M Ϫ1 for ddA; 55 ± 10 M Ϫ1 for ddI and 85 ± 20 M Ϫ1 for ddG-β-CD complexes. ROESY spectra demonstrate that ligands penetrate the hydrophobic cavity of the β-CD. Finally, on the basis of ROESY data, the "low resolution" ddG-β-CD complex structure has been determined by multistep restrained molecular dynamics calculations. Calculated ddGβ-CD complex structure fully agrees with experimental data obtained for other β-CD complexes.