Fusarium wilt of melon, Fusarium oxysporum f.sp. melonis is one of the most important diseases, causing tremendous losses in melon growing areas in Iran. There is a real need for a rapid and inexpensive assay to facilitate accurate disease diagnosis and surveillance for better manage-ment of Fusarium wilt outbreaks. One of the procedures designed for detection of this disease is loop-mediated isothermal amplification (LAMP) assay;its efficiency has been contrasted with polymerase chain reaction (PCR). The translation elongation factor 1-alpha gene is basically used for designing the LAMP (i.e. F3, B3, FIP, and BIP) together with PCR (F and B). Using hydroxynaphthol blue (HNB) dye, LAMP was placed in a water bath after the optimization was done. The results show LAMP is an advantageous method because it is highly sensitive (100-fold), quite cheap, user-friendly, and safe;in addition, it is performed quickly by visual detection and does not require DNA extraction (in direct-LAMP). The LAMP is believed to be a simple and reliable tool for laboratory purposes because it needs only very basic instruments and the results can be observed and contrasted visually.