We report experimental verification of the commutation relation for Pauli spin operators using the single-photon polarization state. The experimental quantum operation corresponding to the commutator, vertical bar I sigma(z), sigma(x)vertical bar = k sigma(y), showed process fidelity of 0.94 compared to the ideal ay operation and vertical bar k vertical bar is determined to be 2.12 +/- 0.18. (C) 2010 Elsevier B.V. All rights reserved.