The FTIR spectrum of the nu6 band of H13COOH has been collected at a resolution of 0.004 cm-1 in the frequency range of 1030-1160 cm-1. The nu6 band was analyzed to be an A-B hybrid band and perturbed by the nearby nu8 band through a-, and b-Coriolis coupling terms. Using a Watson's A-reduced Hamiltonian in the Ir representation, with the inclusion of a- and b-Coriolis resonances, a total of 3004 IR transitions of nu6 have been analyzed to provide rovibrational constants for the v6 = 1 state with a standard deviation of 0.00047 cm-1. The nu6 band was found to be centered at 1095.40365 +/- 0.00003 cm-1. Copyright 1999 Academic Press.