Chemical analyses of major elements (C, N, P, Si, Al, Fe, Ca, Mg) were performed on more than 500 samples of suspended matter from the western Mediterranean Sea. Four samples collected with a free-floating sediment trap were also analysed. The vertical distribution of particulate organic carbon, POC, reported herein is characteristic of oligotrophic mid-latitude regions. In open waters, the concentration of particulate aluminium is nearly constant. A fraction of particulate silicon Si sub(p) is of terrigenous origin, the rest is biogenic. The biogenic fraction of particulate iron and magnesium is noticeable only in the surface layer, where Fe sub(bio)/POC and Mg sub(bio)/POC ratios are about 10 super(-3). It is not possible to estimate the terrigenous and biogenic fractions of particulate calcium.