The use of iridium as a permanent modifier for the determination of lead and cadmium in marine sediment and biological tissues by furnace atomization plasma emission spectrometry (FAPES) was evaluated. The Ir coating procedure, atomization conditions and FAPES parameters were optimized for best analytical response and minimum background signal. Good precision (less than 3% RSD) can be achieved with the proposed method. Certified Reference Materials from the National Research Council of Canada were analyzed to verify the accuracy of this technique. Matrix interference was compensated for by the use of standard additions calibration and good agreement was achieved between found and certified values. Detection limits of 3.8 ng g−1 for Pb and 4.0 ng g−1 for Cd in MESS-3 and PACS-2 marine sediment and 4.1ng g−1 for Pb and 2.2 ng g−1 for Cd in DOLT-2 and TORT-2 biological tissues were o