This paper aims at contributing to a better understanding of the territorial diversities and proximities which are currently taking place in Sardinia. Such an understanding is based on a cluster analysis, applied to socio-economic data at the smallest territorial level (comuni), which is able to identify homogenous groups. The cluster methodology is implemented by using different indicators which should provide a good representation of the socio-economic development of the area. These indicators are per capita income, value added per employee, unemployment rate and activity rate. Once the clusters are identified we look for a better characterisation by examining other phenomena which describe the production structure, the demographic situation and the environment. In conclusion the picture obtained in this way is analysed more deeply by means of some indicators on the economic and demographic dynamics in the early ninities.