In this paper, a robust blind watermarking method for 3D volumes is presented. A bivalued watermark is embedded in the Fourier transform magnitude of the 3D volume. The Fourier domain has been selected because of its important properties in terms of scaling and rotation invariance. Furthermore, a special symmetry of the watermark is exploited, in order to decrease the detection time. The proposed method is proven to be resistant to 3D lowpass filtering, noise addition, scaling, translation, cropping and rotation. Experimental results prove the robustness of this method against the above-mentioned attacks.