The interaction of sulfur dioxide with a Cu(110) surface, oxidized to different levels or hydroxylated, was investigated at room temperature by in situ infrared reflection-absorption spectroscopy. The initial surface chemical state was checked by Auger electron spectroscopy and photoelectron spectroscopy. Oxidation of sulfur dioxide into sulfites or sulfates was observed upon exposure to SO2, depending on the reactivity of oxygen and hydroxyls in the surface layer. The more oxidized the surface, the less reactive it becomes toward sulfur dioxide. Hydroxylation also reduces the surface reactivity as deduced from band intensities. Adsorption of SO2 on Cu(110), only partially covered with oxygen, generates sulfates whereas only sulfites are formed by interaction of SO2 with a surface copper oxide. Coadsorption of sulfur dioxide with oxygen favors the formation of sulfates whether the surface is only partially covered with oxygen or oxidized. When the surface is oxidized and hydroxylated before being exposed to sulfur dioxide, hydrogenosulfates are detected in the adsorbed phase. A mechanism is proposed where hydrogenosulfates are formed by a reaction of SO2 with surface hydroxyl groups. The adsorption sites as well as the symmetry of the identified species are discussed in view of the number and position of vibration frequencies. These in situ IR analyses make clear that the interaction of sulfur dioxide with copper oxide substrate is highly sensitive to the chemical state and to the structure of the oxide surface layer.