A number of problems that might occur if ethanol were used as a blending stock or replacement for gasoline in present cars are identified and characterized as to the probability of occurrence. The severity of their consequences is contrasted to those found with methanol in a previous contract study. Possibilities for correcting several problems are reported. Some problems are responsive to fuel modifications but others require or are better dealt with by modification of vehicles and the bulk fuel distribution system. In general, problems with ethanol in blends with gasoline were found to be less severe than those with methanol. Phase separation on exposure to water appears to be the major problem with ethanol/gasoline blends. Another potentially serious problem with blends is the illict recovery of ethanol for beverage usage, or bootlegging, which might be discouraged by the use of select denaturants. Ethanol blends have somewhat greater tendency to vapor lock than base gasoline but less than methanol blends. Gasoline engines would require modification to operate on fuels consisting mostly of ethanol. If such modifications were made, cold starting would still be a major problem, more difficult with ethanol than methanol. Startability can be provided by adding gasoline or light hydrocarbons. Addition of gasoline also reduces the explosibility of ethanol vapor and furthermore acts as denaturant.