The hydroxyl group on the 2-N-methyl-(R)-((E)-2-butenyl)-4-methyl-L-threonine residue of cyclosporin A was protected by acetylation, then the double bond on the same amino acid residue was oxidatively cleaved using a periodate/permanganate reagent. The resultant derivative of cyclosporin A contained a carboxylic acid group which was subsequently reacted with the nucleophiles 5-(aminoacetamido)fluorescein and poly(L-lysine), in the presence of 1-ethyl-3-[3-(dimethylamino)propyl] carbodiimide, to furnish novel cyclosporin A conjugates.