This article summarizes data on the distribution and development of oak dieback in Romania. Between 1910 and 1961, three periods of oak dieback, each lasting for a number of years, have occurred in Romania. These have involved Quercus robur, petraea, pedunculiflora, pubescens, frainetto and cerris. Among the many organisms isolated are: two species of Ophiostoma, two new species of Erwinia, a Thielaviopsis type fungus and Armillaria mellea. The trouble is complex, involving both abiotic and biotic factors.