The 1-(3-butynyl)pyridinium p-toluenesulfonate salt, C9H10N+.CTHTO3S -, contains a C--H...O hydrogen bond between the acetylenic H atom of the cation and a sulfonate O atom of the anion in the solid state [C...O 3.32 (1), H...O 2.49 A, C--H...O 159°]. The X-ray analysis was complicated by disorder in both the cation and anion. A major (85%) and a minor (15%) component of the 1-(3-butynyl)pyridinium cation are present, both occuping the same volume element in the lattice. The methyl H atoms and sulfonate O atoms of the p-toluenesulfonate anion are disordered over two orientations.