During the infection- while the xylem is colonized by the F. oxysporum f. sp. Lycopersici (Fol)- several effector proteins have been secreted into the xylem that suppress the plant’s defense response and enable parasitic colonization. So far, 14 effector proteins have been reported in Fol. However, there are no identified domains in their sequences. LysM effector proteins were identified in some plant pathogenic fungi and involved in sequestering chitin oligosaccharides. Here, considering the role of LysM effector proteins in plant-pathogen interactions, we searched for candidate effector proteins possessed Lysin (LysM) domains in the genome of FOL. Hence, the LysM domain was searched in the WGS data bank of Fol using Pfam tool and 17 proteins were identified. Two proteins, Fol-LysM1 and Fol-LysM3, were selected based on low molecular weight and present of signal peptide in their sequences. Prediction of the gene structures preformed using FGENESH tools and domain structures and effector characters including signal peptide, number and position of cysteine residues, disulfide bond connectivity and molecular weight of proteins were predicted. The entire nucleotide sequences of the coding region of their genes were determined by PCR and phylogeny of lysM effector proteins was studied. Furthermore, the domain organization of these proteins was compared with that of other lysM effector proteins. This is a first report of detection of lysM effector genes in Fol.