The title compound, C10H18N+·N3−, was obtained by the reaction of adamantadine chloride and NaN3. Within the azide anion, the N—N bond distances are 1.164 (2) and 1.153 (2) Å. Each protonated amantadine cation links with three azide anions via N—H...N hydrogen bonding, forming a supramolecular structure.