This is a ten years research programme and it was sponsored by the Geek Ministry of Public Works, in order to prevent damage in public road services. This research program might serve as an information database for geotechnical properties of swelling soils in Greece. The purpose of this laboratory investigation firstly was to examine the engineering properties and secondly to test the geotechnical behavior as many as possible active soils throughout the Greek mainland and islands. For this, grain size analyses, Atterberg limits, x-ray analyses, shrinkage limits tests,, swell pressure in the oedometer, cation exchange capacity and pH in disturbed and undisturbed soil samples have been investigated. Also an attempt has made to correlate swell pressure and shrinkage limit, with the variables which are water dependable (liquid limit, plasticity index, moisture content), in order to determine one swell potential index and the results were very promising.