Tauari (Couratari guianensis, C multiflora, C oblongifolia, C. stellata, C macrosperma) is a tropical timber very commonly harvested in South America, mainly in different regions of Brazil. It is widely commercialised and exported to European countries to be used for industrial joinery. Important variations of physical and mechanical properties are observed on sawn timber, leading to bitter technological problems for wood manufacturers. These variations could be linked to several factors : nature of the concerned botanical species inside Couratari genus, origin of the trees, variations inside trees. Fourteen series of tests have been carried out on Tauari timber from two origins (French Guiana and Brazil). Four Couratari species have been tested (the four first ones previously mentioned). The main physical and mechanical properties commonly used to characterise any tropical species have been determined according to the CIRAD-Forêt's standard sampling procedure. The variations of some of these properties (specific gravity, shrinkage, compression strength, bending strength, Young's modulus) have been analysed. The results of this analyse underline the respective effect of each studied considered variability factor. In particular, they show that variations inside trees are not negligible as often considered for timber from natural forest by comparison with plantations species. Moreover, species effect reveals that Tauari effectively gathers different quality of wood.