Carbon nanotubes (CNT) and their mechanical properties have been closely investigated since the late 1990s. Initially researches were mainly focused on using of CNTs to reinforce polymer and ceramic matrices, later – on the reinforcing of metallic matrices. Thus, CNT-reinforced aluminium has potential applications in the aerospace, automotive and sports industries where light weight combined with high stiffness and strength is desired. Technologies of nanocomposite metals production are expensive and complex. For this reason it is perspective to apply non-destructive methods and to use specimens with small dimensions for determination of material properties. The specimens with cross-section 10x2 mm and a length of 60, 70, 80 mm was used in the research. Two methods have been used to determine the elastic material properties: an impulse excitation method and a method, based on the three-point-bending tests. Peak-picking method has been applied to determine dissipative material properties. Specimens machined from large billets made of aluminium alloy LM24 with CNT volume content of 0.0, 0.1, 0.3, 0.5 and 1.0% have been tested to determine the influence of the CNT on elastic and dissipative properties of the LM24 alloy. Specimens with free-free boundary conditions simulated by handing the specimens on thin threads have been used in the experiments conducted by the impulse excitation and peak-picking methods. The experimental results show that anchoring of specimen in the upper corners instead of the nodal lines of bending modes didn’t influence values of eigenfrequences and the dependency of loss factor on the frequency, but increased values of loss factor to constant value of 0.00025. The addition of CNT to the aluminium alloys did not yield a visible increase in their elastic properties, but decreased their dissipative properties. If for bending modes the maximal average deviation (in comparison with pure LM24 alloy) is 32%, for twisting modes it is 45%. It is necessary to note that material investigated did contain pores that have considerable influence on the elastic and dissipative material properties. Therefore it was not possible to obtain clear dependences of the material properties on CNT content.