The growing interest on the economic geography issues has provided new vigour to the research efforts aiming at explaining economic phenomena without neglecting space. In particular several studies have focused on the role of spatially bounded externalities on firms agglomeration processes at the local industry level. This paper has a twofold objective. Firstly, we outline a general eclectic model of local economic growth to provide the theoretical background to guide the econometric analysis. The model includes a general taxonomy of different factors which may explain economic growth in a specific industry and location. Secondly, we assess the role of a large set of potential determinants of the process of local agglomeration of economic activity and we address the issue of spatial association of the local growth processes. We apply our model to the case of Italy making use of a very ample database on socio-economic indicators for 784 Local Labour Systems and 97 manufacturing sectors over the period 1991-96. Our econometric results show that local growth in Italy is not a homogeneous process. On the contrary, it is characterized by significant differences across macro regions with respect to the relevance of the explanatory factors. Among the most important determinants of local industry growth, it is worth mentioning the positive role of the diversity externalities. We also find robust evidence of the negative influence of specialisation externalities on labour dynamics at the local industry level. Moreover, we have assessed the effects of other determinants of local growth like: human capital, social environment and public infrastructures. The analysis of spatial dynamics, carried out for the North-East and Centre-North, shows that at the local industry level there are polarisation phenomena at work and that employment dynamics are self-contained within the boundaries of local labour systems once we have controlled for a large set of local determinants.