Natural rubber (NR) when stored for long periods develops higher hardness, as measured by an increase of Mooney viscosity (ML) or Wallace plasticity (P0). Many studies were undertaken to identifY mechanisms that provoke NR hardening during storage especially the involvement of various compounds present in NR including lipids and proteins. These latter compounds have been postulated to be involved in the specific associative structures of NR: the naturally occurring network or gel phase. However, the formation of this complex NR structure or its "dynamics of structuration" over storage time, well known as the "storage hm·dening" of NR, has not been completely understood yet. This present work aims to study NR samples from 3 genotypes (RRIM600, PB235 and GTI). The evolutions of the samples along structuration were followed at the macroscopic scale (physical properties) measuring ML and P0 and, at the mesoscopic scale (macromolecular structure, macro and microgel) using size exclusion chromatography (SEC) and asymmetrical flow field flow fractionation (AsFIFFF) both coupled to a multiangular light scattering detector (MALS). During fast structuration, the rate of the increase of P0 was very different from one genotype to another, especially at the initial period (0-8 hours). According to the genotype, the P0 reached a plateau at different times. After fast structuring, the macroaggregates quantity increased significantly, the density of microaggregates and the quantity of short poly(cis-1,4-isoprcne) chains decreased. It appears from this study that the genotype could help to better understand the dynamic of structuration ofNR. (Texte integral)