The analysis of Natural organic matter (NOM) extracted from the waters of Medjerda dam (Tunisia) by ultraviolet-visible spectrophotometry (UV/Vis), nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR), has showed the heterogeneous nature of NOM and confirmed the importance of the extraction and characterization of the various subcomponents. CHNO/S elemental analysis of NOM has brought out a low content of carbon but a high amount of oxygen or oxygen-containing species, such as carbohydrate-OH and carboxylic groups. The relatively low fluorescence intensity measured for NOM can be ascribed to the aliphatic structure of its constituents and the high degree of non-fluorescent carbohydrates. Polluting solvents such as toluene, benzene, ethyl benzene were also identified in the NOM extracted by GC/MS. The characterization using qualitative speciation has contributed to source recognition of this aquatic NOM. (C) 2012 Elsevier B.V. All rights reserved.