Goal of this study was to investigate and evaluate an impact of two alternative fuels on smoke emissions in comparison to diesel fuel. This study observes three different combustion engine fuels: biodiesel produced by Meroco, Inc. Company (Alternative fuel I); biodiesel produced in factory situated in Sereď (Alternative fuel II); and conventional diesel fuel (Diesel fuel) from Slovnaft, Inc. Company service station. All measurements were repeated three times. Measurements were conducted by free acceleration test at different engine loads. A statistically significant difference (P <0.05) in smoke emissions values was detected between Alternative fuel I and conventional Diesel fuel, and between Alternative fuel I and Alternative fuel II. The difference in smoke emissions values between conventional fuel and Alternative fuel II was not statistically significant (P >0.05). Tested engine has met the requirements of the EURO 3 emission limit values in relation to the measurement results of particulate matter emissions.