The agriculture in Greece was and continues to be an important economic and social sector. This paper examines the basic role of agriculture in the regional economic development in Greece through the use of principal component analysis (PCA) and the SPSS package. Determinants of the differential development rates of the regions and provinces (nomos in Greece) are identified. The basic variables such as per capita output, out put per hectare, farm labour size, rented land, farm size inequality etc. and the components such as productivity of the farm, inequality degree of trading that influences the RED in the regions and provinces (nomos in Greek) are analysed. The results indicate that where the agricultural farms are operated in the traditional family way without dynamic cultivations or cattle-breeding, they are in a disadvantageous position with respect to those regions and nomos where the agricultural farms are operated in an enterprising way, high degree of trading, modern technology, dynamic cultivations and good organization. In the regions and nomos with traditional agriculture, the structure in general is low and the rate of development is low also, where the more modern regions have a better structure, the rate of development is good, the per capita regional income is high and other economic and social indexes are also high.