In the last few years, seismic studies of the upper mantle and transition zone have achieved significant new results in several areas. Progess has been driven largely by the increasing size, quality and accessibility of digital seismic datasets from global and regional networks and from experiments using portable instruments. This paper focuses on a few of the most interesting and important developments. These include: (1) measurements of upper mantle anisotropy, obtained using a variety of techniques, which can reveal details of the flow regimes and tectonic history of the upper mantle, (2) improvements in models of upper mantle velocity and attenuation structure, with some controversy arising regarding how deep slow velocity anomalies extend beneath oceanic ridges, (3) direct seismic observations of topography on the 410- and 660-km discontinuities in the upper mantle, providing constraints on mantle temperatures and dynamics, and (4) observations suggesting secondary seismic discontinuities in some regions.