Grmoire. Mercie@,enstbretame.fi. Ecole Nationale Supkrieure Pdyfechnique FNSP) de Y a m " , B.P. 8390, Yaoundk, Abstract -The authors present a new method to characterise and discriminate oil slicks and some look-alikes in ERSZ S A R images according only to the observed sea roughness, to reduce oil spill detection and monftoring systems cost. It exploit sea wave spectrum images from the multiscale analysis based on a modified morphological pyramid. Many backscatter characteristics extracted at each level, depended on object and background features are normalized to make its spectral scales be identical. Twenty objects (spot and border) backscatter features have been measured. Eleven sea surface slicks types have been analysed, namely oil, atmospheric instability, wind front, unstable air-mass, current front, falling land wind, large gravity waves, low wind area, natural slicks, swell visible and wind sheltered area, The results presented as smoothed basic profires and texfural specfru allow io tackle oil slicks supervised classification in new images. Oil slicks and currentfront are discriminated. But, some ambiguities of sIicks discrimination in SAFt images remain persistent.