The first overtone band of the O-H stretching mode in HOCl has been recorded between 6700 and 7250 cm−1 at a resolution of 0.017 cm−1, which is close to the Doppler limit. Two thousand fifty-four transitions for HO35Cl and 876 for HO37Cl were assigned and analyzed on the basis of a Watson-type Hamiltonian in the S reduction and Ir representation. A set of precise spectroscopic parameters for the v1 = 2 state of both isotopomers has been determined. Band origins were located at 7049.8132 and 7049.8234 cm−1 for HO35Cl and HO37C1, respectively.Copyright 1993, 1999 Academic Press