This paper addresses the question of whether riparian zones and groundwater are ‘hotspots’ of nitrous oxide (N2O) flux in the landscape. First, we describe how riparian zones and groundwater function as transformers of N, with a particular emphasis on mechanisms of N2O production in these ecosystems. We then present specific data on N2O flux in these ecosystems and attempt to reconcile these data with existing regional scale estimates of N flux for Norway and with estimates of N2O flux for Norway produced using the OECD/IPCC/IEA Phase II methodology for calculation of regional and global N2O budgets. While the OECD/IPCC/IEA approach produces estimates of riparian and groundwater N2O flux that are reasonable, given what we know about regional scale N balances and actual data on N2O flux, it does not allow us to determine if riparian zones and groundwater are ‘hotspots’ of N2O production in the landscape. The approach fails to answer this question because it is unable to account for spatially explicit phenomena such as riparian and groundwater processing of excess agricultural N. Research needs that would allow us to address this question are discussed.