Kale leaf had similar contents of vitamin C, $NO_3$, p, Ca, Mg, and Fe with reported values. Among these internal quality factors, $NO_3$ content which has been a concern recently, ranged from 139 to 429 mg in 100 g fresh kale leaf, Kale showed high vitamin C content ranging from 106 to 203 mg in 100 g fresh leaf. The relative concentration of chlorophyll and b value color had a high correlation coefficient (r) with vitamin C, $NO_3$, Mg and Fe content. The relationship between $NO_3$ content and the relative concentration of chlorophyll was given by the following linear equation: $NO_3$ content : 21.55 + (5.907 ${ imes}$ the relative concentration of chlorophyll) with an r of $0.910^{{ast}{ast}}$. Correlation between $NO_3$ content and b value was also very dependable (r = $-0.901^{{ast}{ast}}$). Vitamin C content and the relative concentration of chlorophyll showed a high correlation, r = $-0.858^{{ast}{ast}}$. Among internal quality factors, vitamin C content increased with decreasing $NO_3$ content and their correlation coefficient was high (r = $-0.795^{{ast}{ast}}$). Consequently, $NO_3$ content of kale leaf could be inferred from an external nondestructive method, such as the relative concentration of chlorophyll. We may be able to produce high quality kale leaves containing high amount of vitamin C and low content of $NO_3$ using this method.