This research was conducted to determine if spectral reflectance in the NIR and Mid-IR can be used to identify various levels of herbicide injury in soybean and weed species. Plants were sprayed with various rates of the herbicide glyphosate. Glyphosate inhibits a pathway unique to plants and bacteria and at the point of inhibition a compound called shikimate accumulates in excess. Shikimate is a compound naturally present in plants, but following plant exposure to glyphosate, this compound accumulates in excess. Spectral reflectance was used to quantify the degree of shikimate accumulation in soybean (Glycine max (L.) Merr.), common lambsquarters (Chenopodium album) and redroot pigweed (Amaranthus retroflexus). Shikimate levels were also determined spectrophotometrically. If there is a strong correlation between features in either the NIR or Mid-IR with shikimate levels, a sensor could potentially be developed to identify plants that have been exposed to glyphosate.