A scene containing multiple independently moving, possibly occluding, rigid objects is considered under the weak perspective camera model. We obtain a set of feature points tracked across a number of frames and address the problem of 3D motion segmentation of the objects in presence of measurement noise and outliers. We extend the robust structure from motion (SfM) method [5] to 3D motion segmentation and apply it to realistic, contaminated tracking data with occlusion. A number of approaches to 3D motion segmentation have already been proposed [3, 6, 14, 15]. However, most of them were not developed for, and tested on, noisy and outlier-corrupted data that often occurs in practice. Due to the consistent use of robust techniques at all critical steps, our approach can cope with such data, as demonstrated in a number of tests with synthetic and real image sequences.