Late-season foliar-nitrogen (N) fertilization based on petiole nitrate concentration during boll development is a widely used production practice in cotton. The objectives of this study were: (1) to examine the response of cotton plants to foliar-N fertilization based on petiole N, two boll loads (low and high), and two soil-N levels (low: 55 kg N ha^-1; high: 110 kg N ha^-1), and (2) study the effect of soil-N levels on the petiole characteristics of the leaf positioned fourth from the top of the canopy. High boll load plants in both soil-N level had significantly greater yield than low boll load plants in either soil-N level. Also, the foliar-N sprays in high boll load plants out yielded the non-sprayed high boll plants of high soil-N, as well as, low and high boll plants in low soil-N. Petiole lengths of big leaves in low and high soil-N levels were significantly greater than their small leaves. The same was true for petiole diameter. The petiole diameters, leaf area, and chlorophyll of small and big leaves of high soil-N level were significantly greater than in the low soil-N levels. Petiole dry weight was similar between low and high soil-N levels, whereas the boll dry weight was significantly greater in high soil-N levels than in low-soil-N levels. High soil-N level resulted in greater petiole NO₃ than the low soil-N. These findings suggested that although the petiole characteristics varied between low and high soil-N levels, the size of the sink determined the plants need for additional N, and therefore, governed plant response to foliar-applied N.