Fumonisins (FBs) are harmful carcinogenic natural toxins produced by fungi from Fusarium species whereas found in oilseeds crops. Fumonisin B1 (FB1) and Fumonisin B2 (FB2) are the most serious natural food contaminants among the several known Fumonisin. The main purpose of this study is to establish an accredited rapid and ultra-sensitive method for the investigation of FB1 and FB2 in Egyptian oilseed. LC-MS/MS with the positive-ion electrospray ionization (+ESI) mode has been employed for this investigation. The limits of quantification (LOQ) were 3.9 µg/Kg for FB1 and 2.3 µg/Kg for FB2. The limits of detection (LOD) were 1.2, and 0.7 µg/Kg for FB1 and FB2 respectively with 21% expanded uncertainty. The test method has been used to review six governorates of Egypt on corn, white corn, soybean, sesame, and sunflower seeds. For corn, the contamination levels of total FB1 and FB2 were varied between