Examination of sections in the vicinity of the Gran Sasso chain (northern Italy) has provided data leading to the determination of the inter-Mindel-Riss paleoclimatic evolution. The presence of calcite in rock fissures and on ancient soil surfaces indicates that an interglacial period followed the last cold of the Mindelian--a period of rapid warming which caused the calcite to be precipitated. The formation of travertine can also be attributed to this phase. Clays deposited in the low areas contain abundant organic matter suggesting the continuation of warm, humid conditions in which vegetation developed and pedogenesis progressed. The heat and humidity increased, causing the limestones to dissolve completely to decalcification clays. The ironstone caps observed in the Guimentina valley mark the end of the evolution. After this a climatic crisis developed which involved semitropical processes and mechanical erosion by running water.