In this work, the determination of 19 metallic elements (aluminum, arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, sodium, nickel, phosphorus, lead, vanadium and zinc) in biodiesel samples obtained by homogeneous alkaline catalysis has been carried out, obtained by homogeneous alkaline catalysis, and of the vegetable oils used as raw materials for the production of these biofuels, by inductively coupled plasma atomic emission spectrometry (ICP-AES). For this purpose, it was necessary to perform a previous optimization of the microwave oven acid digestion method for this type of samples. Likewise, the quality of the biodiesel samples, in terms of the legislated metal content, was evaluated by applying the UNE-EN 14538:2006 and UNE-EN 14107:2003 standards. These standards were also used for the analysis of the contents of these five metallic elements in the oil samples used as raw material in the production of biodiesel.