Technical Abstract: Over the past few decades there has been considerable research evaluating sensor-based technologies for in-season application of nitrogen (N). The majority of this work has been done on wheat (Triticum aestivum L.) and corn (Zea mays L.), with little research on other crops. Field studies were established in Brookings, SD to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for measuring in-season N status on canola (Brassica napus L). Sensor readings and plant biomass samples were collected weekly through the rosette to early bud growth stages. The sensor measures reflectance in the red and near infrared (NIR) regions of the electromagnetic spectrum and calculates a normalized difference vegetation index (NDVI). The ability of the sensor readings to measure biomass, plant N uptake, and predict grain yield and protein for each sampling date was determined. In general, in-season plant biomass, plant N concentration, and grain yield increased with increasing N rate. Sensor readings (NDVI) showed a significant relationship with plant biomass, N uptake and grain yield regardless for the sampling dates. Measurements collected in the late rosette growth stage had the highest correlation with plant biomass and grain yield compared to other growth stages. Results suggest that existing sensor-based variable nitrogen technology developed has the potential to be utilized for other non-traditional crops such as canola.