In the Romanian East Carpathians overthrust relations between the Tarcau, the Marginal folds and the Subcarpathian nappes and the Moldavian and Moesian platforms have been deduced from seismic profiles and confirmed by wells. The down steps of the platform, under the nappes, have created many faulted blocks. South of the Trotus Valley, the Pralea-Focsani Depression has developed on the platform basement. Between the Slanic and Dambovita valleys, in the Mio-Pliocene zone, the Subcarpathian nappe, the diapir folds and the Oligocene deep structure have been delineated on seismic profiles. The presence of all the conditions for oil generation and entrapment encourages new investment in geological and geophysical exploration.