The title salt, C5H9N2+·Cl−, exhibits multiple hydrogen-bonding interactions between the cationic imidazole moiety and the chloride anion. The protonated aromatic nitrogen moiety displays the shortest hydrogen-bonding interactions while weaker hydrogen bonding is observed between the aromatic H atoms and the chloride anion. The crystal studied was refined as a two-component inversion twin with a twin ratio of 0.71 (5) to 0.29 (5).