We compared restriction fragment length polymorphisms (RFLPs) of mitochondrial DNA among seven fusarium species. Mitochondrial DNA from F. oxysporum (section Elegans), F. moniliforme and F. subglutinans (section Liseola), F. nygamai, F. napiforme and F.beomiforme (section Dlaminia), F. graminearum (section Discolor) were digested with the restriction endonucleases EcoRI, BglII, Hin dIII, Xbal, PstI and EcoRV. Fragments were separated on agarose gels, used restriction analysis, Southern-blotted, and hybridized with two random probes, a 3.5 kb fragment from F. subglutinans mtDNA and a 1.6 kb fragment from F. napiformemtDNA. RFLP analysis of mtDNA revealed high interspectific variation. The genome size of mitochondria in these seven species ranged from 50. 4 kb to 84.5 kb. Restriction fragment analysis of mtDNA indicated that F. nygamai and F. napiforme were most closely related to each other than to the other species. But mtDNA of F.beomiforme which belongs to same section was distinct from F. nygamai and F. napiforme. southern hybridization analysis revealed no major discrepancy with restriction fragment analysis. These results suggest that F. beomiforme may not be closely related to other two species in Dlaminia