Molecular level understanding of catalysis is fundamental to solve many problems related to activity, selectivity and a host of other issues. Over the years surface science techniques have been instrumental in shedding light into some of these fundamental questions. With the rapid advancement of instrumentation and microscopy techniques, the field of nanotechnology has taken unprecedented dimensions. Catalysis by nanoscale materials is an area, which has benefited most from this. A major area in nanocatalysis is aimed at identifying critical size and shape dependence of these materials towards various reactions of industrial importance. This article is aimed at looking at recent developments in the field of nanocatalysis along with the role of surface science towards understanding the role of active sites in catalysis. (C) 2010 Elsevier B.V. All rights reserved.