Over the recent years, great attention has been focused on ethanol as alternative fuel for both port fuel injection (PFI) and Direct Injection (DI) spark ignition (SI) engines. The higher octane number allows to operate with high compression ratio improving the engine efficiency, and the larger oxygen content contribute to reduce PM emissions. Ethanol can be both blended and dual fueled with gasoline. In this latter case, ethanol and gasoline are separately injected. The aim of this study is to analyze the different methods of ethanol fueling in order to understand the configuration that better exploit the ethanol effect on the reduction of soot formation. To address this issue, the particle emissions from both the ethanol/gasoline blend, E30, and the ethanol/gasoline dual fuel, EDF, were evaluated. In this latter case, ethanol was direct injected and gasoline was injected in the intake duct. For both the operating configurations, the same percentage of ethanol was supplied: 30 %v/v ethanol. The experimental activity was performed in a small displacement single cylinder engine and the tests were carried out at 3000, 4000 and 5000 rpm under full load condition. The particle emissions were measured downstream of a three way catalyst (TWC) by a smoke meter. Particle sizing and counting was performed in the size range from 5.6 nm to 560 nm by an Engine Exhaust Particle Sizer (EEPS). For E30 the particle emissions are larger than for EDF because of the different contribution of gasoline. In EDF the better evaporation and mixing of gasoline, typical of PFI configuration, coupled with the soot reduction tendency of ethanol lead to low particle emissions