【Objective】 To clarify the phylogenetic relationship of four physiological races of Fusarium oxysporum f. sp. cubense (Foc), the causal agent of fusarial wilt of banana.【Method】The ribosomal DNA internal transcribed spacer (ITS) regions of the four physiological races of Foc were first amplified using PCR technique, and then RFLP analysis of the ITS products of these races were performed using three restriction endonucleases including AIu I, Hpa IIandTaq I.【Result】A single 568 bp ITS fragment was amplified specifically from eight strains belonging to four races, respectively, but there was no obvious polymorphism among these races. RFLP analysis of the ITS products from these races showed that the differences among races were very small. 【Conclusion】 PCR-RFLP technique was unsuitable to be used as the identification basis for the physiological races of Foc.