In our paper we try to combine the theories explaining the prevalence of informal work, using a regional approach. Reviewing the literature, we observe that, there is no evidence to confirm that the relationships that occur in cross‐country comparisons remain significant when we use regional data and analyse cross‐regional variations. Our general question is therefore whether there is simply more informal work in less‐developed regions, as the modernization theory asserts. Our analysis concludes that there is limited correlation between the prevalence of informal work and a region's level of development, whereas there is a significant positive autocorrelation between the extent of informal work in the analysed voivodships in Poland.