The scanning electron microscopy (SEM) in backscattered electron mode (BSE), which imaging is based upon atomic number (Z) contrasts between constituents, allows to visualize the organic matter distribution within the sediment. However the precise identification of organic matter is not possible as all the organic matter appears black. The contrasts between the different types of organic matter were enhanced for the use of the SEM/BSE imaging by staining organic matter with high Z elements. Experimental procedure was tested in terms of faisability, selectivity and specificity on polymers containing functional groups likely to occur in sedimentary organic matter. Then staining was applied to sedimentary organic matter, i. e. to purely organic sediments (algal mats, kukersite and coal) and to clayey sediments (Kimmeridge Clay Formation). The chosen staining solutions comprised : ruthenium tetroxide, osmium tetroxide, phosphotungstic acid (PTA) and silver methenamine. Samples were immersed in staining solutions for 24 hours, rinsed and observed with SEM/BSE. The penetration depth ranges between 20 and 150 µm. Other complementary tests with ruthenium tetroxide and mercury acetate were also performed on polymers. Tests with PTA, silver methenamine and osmium tetroxide were satisfying and presented a more or less broad specificity. Osmium allows the distinction of each algal laminite of the algal mat. The different parts of the kukersite react specifically with osmium, PTA and silver. The coal constituents display a specific staining with silver methenamine. Osmium and PTA allow in the Kimmeridge Clay sample (a) to differenciate several types of organic particles according to their chemical composition; (b) to locate the organic matter finely dispersed within the mineral, clayey matrix.