Fusarium yellow disease of chickpea (Cicer arietinum), caused by the vascular wilt pathogen Fusarium oxysporum, is a major production constraint in chickpea-growing regions of Iran. Fifteen isolates of F. oxysporum were classified on the basis of vegetative compatibility (the ability to form heterokaryons). Vegetative compatibility was assessed by pairing nit mutants. The isolates were assigned to three vegetative compatibility groups (VCGs): VCG1, VCG2, and VCG3 with 5, 3, and 7 members, respectively. These isolates were also characterized by virulence assay. On the basis of disease severity on chickpea seedlings, they were divided into three groups: highly virulent (HV), moderately virulent (MV) and weakly virulent (WV).Twelve arbitrary decamer primers were tested on the fungal isolates by polymerase chain reaction. Random amplified polymorphic DNA (RAPD) analysis indicated considerable genetic variation among these isolates. Comparison of the results of VCG tests and the virulence assay indicated that all seven HV isolates belong to a single vegetative compatibility group (VCG3), and all three WV isolates are placed in VCG1. There was no relationship between RAPD groups and the other two characteristics of Iranian F. oxysporum isolates.