This paper aims at investigating the factors affecting relative changes in the average farm size over the period 2000-2010. The objective has been pursued applying an empirical investigation in Tuscany region through observation aggregated at municipality level. By applying spatial analysis and spatial econometric techniques, spatial distribution and determinants of different farm size are detected. Results showing the relevance of spatial analysis, pointed out that farm household and territorial characteristics, such as the productivity, single farm payments and being located at plain altitude, positively affect the average farm size since these agricultural holdings are eased to pursue economies of scale.