Seeking and maintaining high editorial standards of scientific manuscripts is an important responsibility. This task can be accomplished only with the advice and input from a large number of colleagues who are invited to review submitted papers. Their critical comments and helpful suggestions have played a major role in making Vadose Zone Journal a success. Members of the VZJ Editorial Board want to express their appreciation to the following individuals who helped review manuscripts in 2006. We extend our apologies and thanks to any reviewer whose name may have been inadvertently omitted from this list.