The aim of this paper is to identify the endogenous capital of small towns in the Poznań agglomeration and to analyse its role in their development. The agglomeration of Poznań (a NUTS 4 unit) is located centrally in the Wielkopolska voivodeship, which lies in the western part of Poland. There are eight small towns in the Poznań agglomeration that vary in size and socio-economic functions they perform. They belong to two size classes. Those with 5–10 thousand inhabitants predominate; those are Buk, Kostrzyn Wielkopolski, Kórnik, Pobiedziska, Puszczykowo, and Stęszew. The class with the population of 10–20 thousand contains Mosina and Murowana Goślina. Their endogenous capital is identified in terms of three types: endogenous social capital, or population, its resources and quality; endogenous economic capital, or local wealth and production base, free lots and investment areas; and endogenous natural capital, or the condition of the environment, natural resources, and landscape attractiveness. In the analysis of the endogenous capital of small towns of the Poznań agglomeration, the following research instruments have been used: the index method, mathematical-statistical methods, and the survey research technique. The final analysis reveals that in the set of eight small towns of the Poznań agglomeration the highest quality of endogenous capital can be found in Puszczykowo, Kórnik, Mosina, and Murowana Goślina, and the lowest, in the peripheral ones: Buk and Kostrzyn.