Inadequate or excess nitrogen (N) severely impacts yield and malt barley (Hordeum vulgare L.) protein and kernel plumpness. This crop is somewhat unique in its narrow N sufficiency range. Variation across fields with residual soil N and yield potential result in large spatial differences for the optimal N fertilizer rates needed to produce high quality malt barley. Recently developed optical sensing technology combined with variable rate spray controller hardware makes it possible to apply N in-season at an unprecedented small scale. The objective of this study is to evaluate the use of optical sensing instrumentation to help manage in-season N for malt barley by correlating the Normalized Difference Vegetation Index (NDVI) with tissue nitrate, yield, and various crop quality parameters. Five locations were used as evaluation sites in Eastern Idaho. High correlations of R² values of 0.37-0.95 were observed in 4 of the 5 fields when comparing yield with NDVI at Feekes 6 for malt barley. The correlation between yield and N rate were also very high in these fields with R² = 0.50-0.99. Other yield and quality parameters were measured and recorded to further evaluate the optical sensor in malt barley. Trends and correlations showed useful relationships between NDVI and yield and N Rate.