Polyamide/organoclay nanocomposites have been prepared via direct melt intercalation in an internal mixer at 2.5% volume fraction, under various processing conditions. The influence of the melt mixing conditions on the structure and on the oscillatory and steady shear rheological properties of PA-12 layered silicate nanocomposites has been studied. Both structural properties and melt state material properties of nanocomposites were shown to exhibit similar trends when studied as a function of the specific mixing energy. Low frequency storage and loss moduli, but also yield stress and low-shear first normal stress difference were shown to increase up to a critical value of this specific mixing energy, and to level off above this value.