Electroless coatings are obtained by means of an autocatalytic chemical reduction process for depositing different metals. Electroless nickel plating is an engineering coating, normally used for its excellent corrosion and wear resistance. Little information exists about the application of this type of coating on powder metallurgy products, compared with the large amount of data available on coatings on wrought metal products by means of the same technique. The present paper discusses the effect of the different grades (20, 15, 10, 7 and 5%) and types (irregular and regular) of porosity of iron powder metallurgy compacts, on the properties of the electroless nickel coating: thickness, composition, deposition rate, microhardness, porosity, adhesion and corrosion resistance. Sponge and atomised iron compacts with different porosities were obtained by pressing at different densities (5.5 - 7.0 g cm-3) and sintering at 1120 ° C in an N2 - H2 atmosphere. The sintered parts were successfully coated by electroless nickel deposition using a hypophosphite bath with the same composition and conditions for all the compacts, and the coating was subsequently characterised. The ferroxyl test was used to evaluate the grade of superficial porosity, and the salt spray test helped to obtain the corrosion resistance of the nickel - phosphorus deposits on the PM compacts. Electron and optic microscopy techniques were used to analyse the coating thickness quantitatively. Also, measurements were performed to determine the microhardness achieved in the coatings. Results show that, for both types of powder, levels of porosity > 12% cause coatings with deficient properties: low corrosion resistance, high levels of porosity, dispersion in microhardness and low thickness. However, the coatings obtained in the pieces made with the atomised powder have better characteristics than those elaborated with iron sponge powder.