A multi-method experiment was carried out to study humic compounds and metal speciation in a marine sediment sample. The humic and fulvic acid structures were investigated by infrared spectrometry,13 C NMR, thermogravimetry, and elemental analyses. Trace metals (Cu, Pb, Cd, Zn, Fe, Cr, Ni, Co, Mn and Al) were determined in digests of the sample and in solutions obtained by selective extraction procedures. The distribution of metals associated with humic substances has also been investigated by high pressure liquid chromatography using inductively coupled plasma atomic emission spectrometer as detector. The results show that manganese, iron and aluminum are present in inorganic form, whereas 37% of nickel and 8.8% of copper are present in the metal-humic compound form.