Studies were conducted to determine the sediment oxygen demand (SOD) of a created urban wetland, the cause of differences between SOD methods, and the effect of temperature on the rate of exertion of SOD. <i>In situ</i>, laboratory tank, and laboratory core methods were employed to measure the SOD. It was observed that the main cause of differences in the results obtained by the three methods was differing water volume to sediment surface area (V/SA) ratios. SOD was found to increase with increasing V/SA ratios. By approximating the V/SA ratio of the marsh, the SOD for the system was estimated to be 3.08 g/m²/day. A 10°C rise in temperature was observed to more than double the SOD rate. / Master of Science