The goal of this paper is to analyse the individual impact of tax rates and agglomeration rents as well as their interaction on location decisions of manufacturing firms within Belgium. Theoretically, both location determinants may weaken each other’s impact. Using a unique 10-year dataset concerning the number of newly setup firms at the sector level for 43 Belgian districts, we show that local effective tax rates have a negative impact on location decisions. Moreover, location-specific supply-side agglomeration rents attract new firms and their impact appears to be even stronger for more spatially concentrated sectors. Finally, we show that a higher effective tax rate in a district does not necessarily deter new firms in more agglomerated districts, pointing to the existence of taxable location-specific agglomeration rents.