Measuring the quality of three-dimensional 3D reconstructed by transmission electron microscopy is still an open problem. In this article, we extend the applicability of the spectral signal-to-noise ratio (SSNR) to the evaluation of 3D volumes reconstructed with any reconstruction algorithm. The basis of the method is to measure the consistency between the data and a corresponding set of reprojections computed for the reconstructed 3D map. The idiosyncrasies of file recosntruction algorithm are taken explicity into account by performing a noise-only reconstruction. This results ill the definition of a 3D SSNR which provides all objective indicator of the quality of the 3D reconstruction. Furthermore, the information to build file SSNR call be Used to produce a volumetric SSNR (VSSNR). Our method overcomes file need to divide the data set in two. It also provides a direct measure of the performance of the reconstruction algorithm itself; this latter information is typically not available with the standard resolution methods which are primarily focused oil reproducibility alone. (C) 2004 Elsevier Inc. All rights reserved.