In Nova Scotia, a shift has occurred focusing on constructed wetland systems as an effective treatment option for agricultural wastewater.� Although much research has examined the water quality treatment aspects of these systems, there has been limited interest in examining the air quality effects.� As such, the objectives of this study were to examine the changes between growing season (GS) and non-growing season (NGS) greenhouse gas emissions from these living treatment systems.� Six pilot-scale (6.6 m2) constructed treatment wetlands were established at the Nova Scotia Agricultural College's Bio-Environmental Engineering Centre in Truro, Nova Scotia, Canada.� The wetlands were constructed to allow for continuous wastewater loading at two rates: typical (70 L d-1) and high (140 L d-1) and contained either aquatic vegetation (cattails) or no vegetation.� Each wetland had a removable chamber to allow for continuous measurements of CO2, CH4, and N2O emissions using a mass balance approach.� During the GS, average CO2 uptakes were large (approximately -40 g CO2 m-2 d-1) for the wetlands with dense vegetation (approximately 100% cover) at the typical loading rate.� For those wetlands at higher loading rates, CO2 emissions were observed to be as high as +11 g CO2 m-2 d-1.� Methane emissions from the wetlands were closely related to the presence of plants and wastewater strength.� Wetlands with typical wastewater loading rates and an abundance of aquatic vegetation produced average CH4 fluxes of approximately 35 mg m-2 d-1, while higher wastewater strength systems with little vegetation approached 85 mg m-2 d-1.� During the NGS, all vegetated wetlands exhibited higher CH4 emissions than the non vegetated systems.� Nitrous oxide emissions were generally negligible for all the wetlands, regardless of time of year.�