Denitrification, the anaerobic microbial conversion of nitrate to nitrogen gases, is key to the ability of riparian zones to function as nitrate sinks or buffer zones in the landscape.  While many field and laboratory studies have demonstrated that this process is strongly controlled by levels of soil oxygen, nitrate and carbon, expression of these controls at the riparian ecosystem scale is complicated by hydrologic controls on nitrate movement into and through the riparian zone.  As a result, factors such as flowpath configurations connecting uplands and streams, riparian water table depth, and the presence of seeps are the ecosystem and landscape scale controllers of riparian denitrification rates.  These factors are in turn regulated by watershed and regional scale factors such as land use and geology.  We argue that control of denitrification rates in riparian ecosystems can be evaluated by focusing on three connections; 1) flowpath connections between uplands and riparian zones, 2) hyporheic and flooding connections between riparian zones and streams and 3) carbon connections between surface and subsurface soils involving dissolved organic carbon and buried horizons.  New tools such as 14-carbon dating and ecohydrological modeling based on high resolution geospatial databases will allow us to focus on these connections to improve evaluation of riparian denitrification and protection, management and restoration of riparian nitrate sink functions in landscapes.