Health impact assessment (HIA) is an approach that has experienced increased activity and wide support within England. This is reflected in the large number of HIAs being undertaken at local and regional levels, by the advocacy of HIA in many national policy documents, and by the setting up of specialized HIA posts and centres. To continue this level of support, and to justify any increase, the approach of HIA must show whether and how the HIA approach informs the decision-making process and, in particular, whether it improves health and reduces health inequalities. The first steps in answering these questions have been taken by the partial evaluation of some completed HIAs within England. A description of these evaluations is presented. Work is also progressing on promising practice guidance for practitioners on the topic of evaluating HIAs. The further development of evaluation within HIA is required, at both a practitioner and research level, and provides an exciting opportunity for people and groups to advance the evidence base for HIA, while also proving its place as an effective public health intervention.