The dependence of the total neutron cross section of crystalline and liquid aluminium was studied for energies between 0.003 ev and 0.009 ev. The results obtained for crystalline aluminium have shown that in the case of absence of texture they are in fair agreement with the calculated values. The study of liquid aluminium has shown that the scattering cross section determined by subtraction of the calculated absorption cross section from the measured total cross section, in the studied range, decreases with increasing wavelength.