Field studies were conducted over three seasons to determine the effect of N and K on susceptibility of tomato to bacterial spot. A factorial randomized complete block design consisting of four rates of N (167, 334, 501, and 668 kg·ha–1) and three rates of K (334, 668, and 1335 kg·ha–1) were used. Liquid fertilizer was injected via trickle irrigation. Increasing N rates reduced disease severity, whereas the effect of increasing K was inconsistent from season to season. The concentration of N in leaf tissue showed a significant negative correlation with disease severity, whereas the concentration of Ca in leaf tissue exhibited significant positive correlation with disease severity and negative correlation with N rate during two seasons of data collection.