We have observed OH radical products from the unimolecular dissociation of ethyl hydroperoxide (CH3CH2OOH) excited to 5v(OH) and have collected an action spectrum from 15 600 to 16 800 cm(-1) and an OH product state distribution at the maximum (16 119 cm-1). We use a vibrational-torsional model to simulate spectra in the 5v(OH) region for the trans and gauche conformers. A combination of the two simulated spectra resembles the experimental action spectrum, provided that the trans conformer is assumed to dominate at room temperature. Energy disposal in the OH fragment yields an upper limit for the O-O bond dissociation energy at D-0 < 44 kcal mol(-1).