The introductory part of the article is devoted to a review of concepts of economic base and methods of measurement of economic base. The author presents K. Dziewoński’s concept of economic base who divided economic function of city into two groups: endogenous (non-basic ) and exogenous (basic). Out of a number of methods, H. Hoyt’s method of surplus employment has been chosen (1944). According to this method, surplus employment is identical to exogenous employment. The surplus employment is obtained by subtracting the employment necessary for self-sufficiency from the actual employment in a particular industry of the city. The surplus employment is calculated as follows: Znadw. m = Zim -(Zm‧ZiM/ZM) Znadw. m - exogenous employment in the city m, ZiM - employment in i industry in the city m, ZM - total employment in i industry in the whole area, Zm - total employment in the whole area, - total employment in the city m. The author’s analysis is based on a group of 21 towns in Olsztyn voivodship (north-eastern part of Poland). The data from the 1960 and 1970 censuses is used in the analysis. Most of Olsztyn voivodship towns were founded in the Middle Ages by Teutonic State. The history of these towns was very stormy. One should mention here Polish-Teutonic wars of the 15th century, Napoleonic wars at the beginning of the 19th century and two world wars. The area suffered most during the Second World War. For example, in 1938, -today’s Olsztyn voivodship towns had 232 305 inhabitants and in 1946 only 81 018 inhabitants. The author described the modern (after 1945) history of this area and changes in the settlement structure. All the towns were divided into several functional groups. In 1960 there were seven groups The towns had the following functions: - agricultural function, - manufacturing function, - transport and communication functions, - trade function, - public health service, social welfare, physical culture functions, - administration and others, - multifunctional. In 1970 there were no towns with trade function and public health service or similar functions. Five town in 1960 had agricultural function (Bisztynek, Górowo Iławeckie, Jeziorany, Nidzica, and Sępopol). Seven towns specialized in manufacturing (Bartoszyce, Dobre Miasto, Iława, Kętrzyn, Morąg, Ostróda, Szczytno). Only one town, that is Korsze, had transport and communication function. It was an important railway station on the way from north-eastern Poland to the Baltic seaside. Two other towns (Biskupiec and Lidzbark Warmiński) had trade function. One town (Mrągowo) was classified as town with specialization in public health service. The capital city of voivodship, Olsztyn, had administration function. Another town in this group was Barczewo, small satellite-town not far from Olsztyn. Reszel and Lubawa were the towns without specialization. In 1970 Bisztynek, Nidzica and Górowo Iławeckie bad agricultural function (like in 1960). Lubawa and Olsztynek had also this kind of specialization (in 1960 multifunctional towns). Bartoszyce, Dobre Miasto, Kętrzyn, Szczytno (similarly as in 1960), Mrągowo and Reszel had manufacturing functions. Three towns: Korsze, Iława and Ostróda had specialization in transport and communication. Olsztyn, Morąg, Biskupiec and Lidzbark Warmiński had administration function. The last group were multifunctional towns. There were three multifunctional towns, Jeziorany, Barczewo, and Sępopol. The author goes on to describe the economic base of Olsztyn voivodship towns as a whole. For 1960 and 1970 the author calculated the exogenous function average for all the towns in the group, divided into four sub-groups (up to 5 000 inhabitants, 5 000-10 000 inhabitants, 10 000-50 000 inhabitants and over 50 000 inhabitants). Small towns had agricultural and service functions but bigger towns specialized in service and manufacturing. In conclusion the author noticed that the historical factor exerted a great influence on development and growth of these towns. The Olsztyn voivodship is an agricultural region of Poland and this factor was recorded in the group of 21 voivodship towns. Modern agricultural production needs service, and this function was fulfilled by several towns. Some towns (the biggest in the analyzed group) had manufacturing function. The author sugeested that manufacturing and services are likely to be the most important factors of town growth in the future.