Expanded environmental awareness and asset consumption are pushing the industry to make fuels from renewable sources that are more readily available in nature. Biodiesel is an alternative diesel fuel that is produced from vegetable oils, reused cooking oils or animal fats. Compared to regular diesel, biodiesel is actually more financially focused in terms of its renewability, biodegradability, low emission profile, non-toxicity and high ignition point. Furthermore, biodiesel increases lubricity, which extends the life of the engine and reduces the frequency of replacing engine parts. The primary problem that slows down the use of vegetable oil as a fuel is its higher viscosity along with low volatility and poor cold flow properties that affect the legitimate operation of diesel engines. Many conventional crops (sunflower, soybean, canola) and nonconventional (palm oil) oilseeds have been studied and are considered good fuels for diesel engines. Transesterification is a process of redistribution of fatty esters (oil or fat). This mostly happens with alcohol (methanol or ethanol). Changing conventional oils to biodiesel is a productive technique for obtaining biodiesel with characteristics similar to fossil fuel. Biofuels are less polluting alternatives because they are not fossil fuels. The oil content of soybeans is about 19%, while oilseed rape and sunflower have 38 and 42% of oil, respectively. Oil production (in kg/ha) of both rapeseed and sunflower also surpasses soybeans. In addition to the three oils already mentioned (rapeseed, sunflower and soybean), coconut and corn oils were studied. Transesterification was used with ethanol via base catalysis using a sodium hydroxide catalyst.