It is well known that serological methods are very useful for detecting some plant pathogens. In this study, the antisera of five Fusarium spp., i.e., F. moniliforme, F. solani, F. oxysporum, F. roseum and F. semitectum were used to investigate the serological relationships between them. Results illustrated that, there was a specificity as for F. oxysporum for infection with sesame cv. Giza-32 and sesame cv. Tushka-1. Polymerase chain reaction (PCR) detection of F. oxysporum isolates using F1 & F2 primers, showed a positive reactions with ten F oxysporum isolates. DNA extracts of F. solani, F. moniliforme and F. oxysporum gave positive reactions compared with the positive control. PCR technique was able to detect very low amount of nucleic acid extracted from F. oxysporum in a dilutions ranged from 10"' to 10*9. In addition, rest Its showed that the F1 & F2 primers were useful for detection of 12 Fusarium is dates collected from different locations. It could be concluded as PCR using the two primers would provide a powerful tool for detection of F. oxysporum isolates.