Tan spot, caused by Pyrenophora tritici-repentis (Ptr), has become a devastating foliar disease of wheat especially under conservation agriculture practices, and where susceptible cultivars continue to be grown over large areas. Race structure analysis was performedby testing 84 single spore isolates of Ptr sampled from durum wheat varieties in Tunisia. Six Ptr races including 2, 4, 5, 6, 7 and 8 were identified for the first time in Tunisia. Race 2 is identified for the first time in North Africa although it occurred at a low frequency rate (5%). However, races 5 and 7 were the most frequent, representing 39% and 43% of isolates tested, respectively. The occurrence of six races on durum wheat is a clear indication of high diversity of Ptr population in Tunisia. Therefore, in order to develop durable resistance to tan spot, the identification and characterization of resistance genes is of crucial importance to national and international research institutions. In this context, a core collection of durum wheat landraces from Algeria (104), France (45), Italy (185), Morocco (117), Portugal (187), Spain (63), and Tunisia (145) were assessed for their resistance at seedling and adult plant growth stages under controlled and field conditions with four local Ptr isolates (races 2,5,7 and 8). Different levels of resistance were observed amongst the tested collection indicating that they may be potentially possessing different resistance gene(s). Hybridization and selection schemes involving these sources of resistance could result in production of durable resistance in durum varieties. These varieties can be commercially cultivated in areas prone to tan spot under conservation agriculture and still not suffer the losses due to tan spot.