Ethylene is involved in the regulation of many processes including leaf expansion and abscission, and can significantly affect plant growth and yield. Stress can induce increased ethylene production, but little is known concerning nutritional stress effects or stress associated with specific nutrient deficiencies on ethylene production. We investigated nitrogen fertility effects on ethylene evolution in whole cotton plants grown in different day temperatures, and attempted to establish a pattern for ethylene evolution throughout development for these parameters. Plants were grown under 0, 50, 100, or 150 kg N ha^-1 applied as NH₄NO₃, and under 28 C or 35 C day temperature. Plants were sampled every 2 wk from 20 to 63 days after emergence (DAE). Ethylene was collected using a flow-through system where air is supplied to a plant in gas-tight glass chambers, and the sample stream flows directly into a gas chromatograph. Ethylene evolution across all N levels and temperatures significantly decreased linearly throughout the sampling period. No differences among N levels or between temperatures were found at 20 and 21 DAE. At 34 DAE, plants grown in 0 kg N ha^-1 at 35 C were significantly higher in ethylene evolution than the remaining N levels, and revealed a quadratic response for this relationship. At 48 DAE, plants grown at 35 C had significantly higher ethylene evolution at 0 and 50 kg N ha^-1 than at the two higher N levels, and revealed a linear response to N fertility. A significant negative linear response to N fertility for plants grown at 28 C was found at 63 DAE. No temperature effect on ethylene evolution was detected throughout the study; however, these preliminary data suggest that ethylene evolution increases when nitrogen deficiency occurs.