The area 60 km northwest of Athens is underlain by swelling soils, mostly of the 'terra-rossa' type. Laboratory tests were performed in order to examine the effectiveness of various methods in alleviating the adverse results of seasonal swelling-shrinking especially in connection with roads and foundations of buildings. It was found that the order of effectiveness of additives was (i) 4% cement and 2% lime, (ii) 6% lime, (iii) about 6% cement, (iv) 6% polymer (polybutadiene) and (v) lime in the free water. It was also found that swelling can be reduced substantially by simple mechanical stabilization, i.e. surcharge and/or dissociation and recompaction.