This article aims to econometrically identify factors determining the export performance of Polish manufacturing firms. A logit analysis is conducted based on a set of quantitative and qualitative data obtained from a combination of two databases of financial data and the results of a direct survey of 470 entities. The results confirm the basic postulates put forward within the contemporary strand of theoretical literature regarding what are known as heterogeneous firms. Exporters differ from non-exporters in a number of aspects, including size, productivity and innovation performance. In the studied sample, the probability of exports depends above all on the presence of foreign capital and is significantly higher for larger and more productive entities.