To promote utilization of renewable fuels in transportation sector, the Thai government has actively sought to obtain higher-ratio ethanol blends in gasoline as early as 2007, at which time E85 was introduced and fuel specifications were determined. The purpose of this study is to evaluate E85 fuel performance in flexible-fuel vehicles (FFVs) with considerations for tailpipe emissions, formaldehyde, acetaldehyde emissions, evaporative emission and vehicle performance. These findings will aid future research in ethanol blends.All tests were conducted utilizing three Volvo S40 FFVs and four specific ethanol blend fuels: E10, E20, E50 and E85 (E-Fuels, collectively). Tailpipe emission tests were conducted in full compliance with Thailand Industrial Standard Institute; TIS 2160 - 2546 (Euro 3 legislation).The three FFVs employed in this study demonstrated a comparable tendency toward reduction of hydrocarbon (HC) and carbon monoxide (CO) as ethanol content increased; however, acetaldehyde concentration increased slightly in all cases, E85 exhibiting the highest acetaldehyde yield. Fuel consumption of E85 increased between 35 and 38% over that of E10. Evaporative emission test results were in full compliance with Euro 3 limit values (≺2 g/test) for all E-Fuels, E85 the lowest of these due to reduced raid vapor pressure (RVP). There was not a significant difference in full-load power among E-Fuels.