A set of experiments to determine the flammability limits of pure and binary blends of fuels was carried out in a combustion tube operated at atmospheric pressure. The lowest and highest volumetric fraction of vapor fuels that allowed flame propagation when the air/fuel mixture was submitted to a high voltage spark with energy higher than the minimum ignition energy defined the lower and upper flammability limit, respectively. The obtained experimental results for liquefied petroleum gas (LPG), acetone, ethylic alcohol, gasoline, diesel, and bioethanol are in close agreement with results reported in the literature. Diagrams of flammability limits of mixtures of gasoline/bioethanol and diesel/biodiesel were found within the range of composition of standard commercial blends of these fuels available formarket in Brazil. The autoignition temperature and the influence of temperature on flammability limits of pure ethanol and a commercial mixture with 4% of biodiesel and 96% of diesel were experimentally determined.