In this paper, a simple procedure for the determination of Si in vegetable oils and biodiesel of different origins by high resolution continuum source flame atomic absorption spectrometry is proposed Samples were diluted with xylene, and external calibration was performed with calibration solutions prepared with xylene and mineral base oil used for viscosity matching. The accuracy was assessed using recovery tests and comparing the results for a set of vegetable oils and biodiesel to those determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Recoveries at 3.0 and 5.0 mg L-1 levels using organic Si standard spiked solutions ranged from 93 to 113%. The limit of detection at the optimized conditions in the original sample was approximately 0.60 mg kg(-1), which is adequate for the analysis of vegetable oils and biodiesel according to the Brazilian legislation.