Fuel blends containing ethyl alcohol, which are now called biofuels, have a long history. Spirit was considered as an alternative or supplementary fuel for car engines already at the turn of the 20th c. It started to be widely used as fuel in the inter-war period. The interest in using spirit as a fuel resulted both from the situation on the raw material market and the need to find new possibilities of marketing alcohol, which was mass-produced in many countries. A breakthrough in this respect was the cheap technology of spirit dehydration worked out in France in the 1920s (dehydrated alcohol was the most effective component of fuel blends). It facilitated a fast growth of the production of fuel spirit. The sales of this product in France and Germany reached 20 million litres per year in the late 1920s, and in the 1930s the figure was redoubled. This growth occurred after both countries made it obligatory to add sprit to fuel blends. The same obligation was later introduced by other European countries, as a way of promoting the relevant sectors of industry and agriculture. This example was also followed by Poland, in which the possibility of producing biofuel were permanently limited. Despite the availability of domestic petroleum and the low degree of motorization the authorities, pressed by the influential agricultural lobby, decided that fuel blends would be the most prospective method of utilizing a large portion of the output of the distilling industry. Having conducted necessary research and having signed a contract for spirit dehydration with the rectification plant in Kutno, the State Spirit Monopoly started to sell fuel spirit in 1929. The beginnings were difficult, though, since the new fuel component was sabotaged by the domestic petroleum industry as competing with its products. Additionally, the regulations concerning the State Spirit Monopoly made it impossible to obtain sufficiently cheap fuel spirit in distilleries. Both those problems were solved in the 1930s. In 1932 new regulations concerning the spirit monopoly were implemented, dividing distillery output into two quotas and lowering the cost of buying alcohol for non-consumer purposes. In the following year the Monopoly signed a long-term contract for selling dehydrated spirit in fuel blends with the Petroleum Industry Syndicate. Petroleum companies, threatened with the perspective of legal obligation, agreed to buy a yearly quota of spirit, amounting to 9% of the sales of petrol on the domestic market (alcohol was to constitute 16-22% of the fuel blend). Another agreement, operative since the beginning of 1939, increased the share of spirit in the sales of fuels to 15% of the sales of petrol (the price of spirit was supposed to be proportionate to the cost of petrol, therefore the sales remained unprofitable for the Monopoly). The aforementioned contract with the petroleum industry resulted in a marked increase of fuel spirit sales as of the budget year 1933/1934; later the sales were dependent on the conditions of the contract, the situation of the fuel market and the increasing consumption of fuel by the army. The sales of dehydrated spirit stabilized at 7-10 million litres yearly at first, and in the year 1938/39, due to the boom in the economy and the increased army purchases, they exceeded 22.5 million litres. The dominant buyer of spirit were the petroleum companies associated in the Polish Petroleum Exports, bound by the aforementioned agreement, which accounted for 50-60% of the sales; c. 30% was purchased by the army; the rest was sold to small unorganized petroleum companies and to research institutions. The positive results of adding alcohol to fuel blends (including their usefulness for military purposes) became apparent only in the last years before the outbreak of WW II. In the economic conditions of the epoch spirit fuel blends fulfilled their intended role and contributed to the success of the government’s economic policy. The increased sales of fuel spirit was an incentive for the development of distilleries and alcohol dehydration plants; they also stimulated research on new technological applications of spirit. Although representatives of fuel industry repeatedly raised the question of driving domestic petrol out of the market by spirit, the usefulness of fuel blends was becoming more and more clear in view of the increasing motorization of the country, which meant a fast approach of the moment in which the domestic production of petrol would become insufficient.