In Poland, small towns constitute the largest group within the overall structure of the urban settlement network. They are distributed evenly across the country and serve numerous essential social and economic functions. These centres thus represent an important link in the system of connections between the countryside and the cities of regional and national significance. According to data for 2017, Poland had 705 such small towns (i.e. towns with less than 20,000 inhabitants). In line with the accessibility of statistical material and the timing of the study (the 2008‑2017 period), the analysis encompassed 670 small towns. The purpose of the work this paper details has been to determine the relationship between the natural increase and the net migration balance in small towns, and to assess their impact on the contemporary population ageing processes in settlement units of this type in Poland. A first phase to the study determined the aforementioned relationship, seeking to avoid the influence of incidental annual changes by averaging indicators for natural increase and net migration balance for the initial and terminal periods of analysis over periods of three consecutive years, i.e. 2008‑2009‑2010 (2008/2010) and 2015‑2016‑2017 (2015/2017). Eight demographic categories of small town were distinguished, with these featuring various directions to the increase/migration balance relationship referred to. In general terms, the first four categories (A, B, C and D) refer to units in which population increased, while the subsequent four categories (E, F, G and H) relate to towns manifesting population declines. A further step then entailed determination of the rate of population ageing in the small towns under study, using the demographic old-age indicator based on percentage-point differences between the shares of the young and old populations (Długosz, 1997). The set of towns analysed was dominated by the centres in which there was significant migratory outflow and/or natural decrease. In the period adopted as the starting point of the study (2008‑2010), the category proving dominant comprised towns whose negative net migration balances were not compensated by positive natural increase (category H). In turn, where data for the final years of the study (2015‑2017) were concerned, the highest proportion of the small towns considered were in category G, as featuring both a high level of migratory outflow and natural decrease. The share of towns representing progressive demographic cateo ies decreased over the entire period considered. The study demonstrated that both the natural and migratory processes ongoing in small towns had assumed predominantly negative directions, leading to weakened population potential, and exerting a direct impact in the form of depopulation. Furthermore, the share of towns in which ageing of the population was observed increased from 65% to more than 80% in the years 2008/2010‑2015/2017. The population-ageing process was thus taking place in almost all of Poland’s small towns, with there remaining just 10 such towns in which the age structure of the resident population was growing younger. The most major changes were those ongoing in the small towns of north-western and east-central Poland. Above all, these were centres experiencing high levels of migratory outflow. The slowest rates of ageing were in turn observed in small centres located in the southern belt of provinces. The results obtained offer confirmation of intensifying population-ageing processes in Poland’s small towns. In future, this will phenomenon s certain to exert a negative influence on the state of the economy in small towns, as well as on their social structures.
