Evaluating environmental governance processes is a precondition for their improvement in contexts of change. In order to do so, one can (1) examine the outcome of a governance process, which consists of outputs and their consequences, or (2) look at the governance process itself. Outcome-oriented and process-oriented approaches have different strengths and weaknesses. This paper discusses the challenges associated with both options when applied to European biodiversity and water governance – namely the implementation of the Habitats and Water Framework Directives. Current evaluation practice focuses mainly on outcomes. Can the process-oriented approach reduce or compensate for the weaknesses of outcome-oriented evaluation? We argue that there are three reasons why it makes sense to combine both approaches: a normative reason, relating to good governance; a substantive reason, relating to the complexity of governance; and a third, instrumental reason concerning the governance cycle. A combined approach makes it possible to evaluate governance processes convincingly with regard to all criteria associated with ‘good governance’. This paper also describes some of the challenges posed by such a combination; these require particular attention, given that existing concepts are not yet sufficiently sensitive to the distinctions between process and outcome orientation.