In Greece, biodiesel, in the form of Fatty Acid Methyl Esters, is produced since 2005 and currently mixed in the Diesel fuel at about 5.5% vol., this percentage being slowly but steadily increasing. The production capacity of existing biodiesel factories in Greece can supply the required quantities to increase the biodiesel blending percentage up to 15%, provided that the necessary vegetable oil and recycled oil quantities should become available and prices be favorable. According to Greek legislation, at least 30% of the raw material must be domestically produced. This need is covered mainly by recycled cooking oils and only secondarily by energy crops in Northern Greece. The author examined the effect of biodiesel fuel on performance, efficiency, emissions and injection system durability of conventional and modern Diesel engines under steady state and transient operating conditions. As a general conclusion, it should be emphasized that the use of low to medium percentage biodiesel blends will be a workable solution both for the common rail engines of modern agricultural tractors and the wide variety of older equipment that is and will be in use for many years to come.