Productivity of wetland biota is one of the key criteria that the Alberta government uses to determine if land leased to oil sands mining companies is restored. Oil sands process water (OSPW) is enriched to contain potentially toxic concentrations of salts and napthenic acids, compromising its value in wetland reclamation procedures. We determined how Chironomid productivity is affected by the water from oil sands process material (OSPM)‐affected wetlands in 10‐d in situ and laboratory bioassays that used water from three OSPM‐affected wetlands compared to or mixed with water from three reference wetlands of similar age. Parallel studies were conducted with Chironomus riparius lab‐cultured larvae and Chironomus sp larvae cultured from egg masses collected from an OSPW‐affected wetland. In situ, Chironomids were housed in 10 cm (ID) 30 cm tall cylinders with fine‐mesh netting windows that allowed water exchange and contact with the sediment. Production of Chironomids emerging from study wetlands was estimated by collecting exuvia in floating hoop traps and adults alighting on sticky traps. Preliminary results suggest that native and lab cultured Chironomids are not equally sensitive to OSPW.