The Mn ion in the title complex, [MnCl(C(17)H(27)N(5))]ClO(4)·CH(3)CN, is six-coordinated with a geometry inter-mediate between penta-gonal pyramidal and heavily distorted octa-hedral. In the macrocycle, the pyridinium ring makes a large dihedral angle of 63.70 (9)° with the best plane through the remaining four N atoms. This feature is common for 17-membered N(5) rings, in contrast to their 16- and 15-membered analogues which often form planar N(5) systems. In the crystal, N-H⋯O and C-H⋯O interactions help to establish the packing. The perchlorate counter-ion is rotationally disordered around the chlorine centre, with occupation factors of 0.74 (1) and 0.26 (1).