Abstract. This paper proposes an empirical analysis of the sensitivity of Discrete Choice Model (DCM) to the size of the spatial units used as choice set. This is related to the well-documented Modifiable Areal Unit Problem). Employment location choices in Brussels, Belgium are used for the case study. DCMs are implemented within different Land Use and Transport Interactions (LUTI) models (UrbanSim, ILUTE) to forecast jobs and household location choices. Nevertheless, no studies have yet assessed their sensitivity to the size of the Basic Spatial Units (BSU) in an urban context. The results show significant differences in parameter estimates between BSU level. Under the assumption from the LUTI model that new jobs are distributed among the study area proportionally to the utility level predicted by the DCM for each BSU level, it is demonstrated that the spatial distribution of these new jobs varies with the size of the BSUs. These findings indicate that the BSU level used in the model can influence the output of a LUTI model relying on DCM to forecast location choices of agents and, therefore, have important operational implications for land-use planning.JEL classification: C25, R30