Development of immune response against cutaneous leishmaniasis initiates after exposure to Leishmania and the intense of the response increases till cure of the lesion, there is a significant difference between IFN-γ of leishmaniasis patients (all types) and healthy volunteers, also there is a significant difference in IFN-γ of CL patients with healing form and non-healing form. The gene discussed is IFNG; the disease is cutaneous leishmaniasis.