The water solubilities in gasoline/oxygenate (MTBE and five alcohols) mixtures were determined using the cloud-point method in a newly designed apparatus. Significant modifications and improvements were made to the Green and Yan apparatus, which uses light scattering to indicate the cloud-point. The experimental data show that the water tolerance of the gasoline blends increases as the carbon number of the alcohol oxygenate increases from one to three and then plateaus for 1-butanol and t-butanol. MTBE has the least water tolerance of any of the oxygenates studied. The water-solubility data were modeled successfully with UNIQUAC using either isooctane alone or an isooctane, p-xylene, isohexene blend to represent the gasoline.