In recent years, active optical crop sensors have been gaining importance to determine in-season nitrogen (N) fertilization requirements for on-the-go variable rate application.  Although most of these active in-field crop sensors have been evaluated in corn and wheat crops, they have not yet been evaluated in soybean production systems in North Dakota. Recent research from both South Dakota and North Dakota indicate that in-season N application in soybean can increase soybean yield under certain conditions.  This study was conducted to evaluate the use of Ag leader OptRx sensor in soybean production to determine the N need. The data for this research were collected from North Dakota State University, NDSU NW22 plots in Fargo in 2013. A field plot experiment was conducted with 2 drainage treatments, 4 varieties, 6 N treatments and 4 replications. Two OptRx sensors, mounted on a small tractor were used to collect the Vegetation Index (VI) values over the study area on 5 different dates throughout the growing season. Each plot (7.6m x 1.5m) consisted of 4 rows. The sensor data were collected from the middle two rows to eliminate the edge effects. The VI data were exported to ArcGIS to calculate the mean VI for each plot. For the last date (87 Days After Planting [DAP]) of data collection in the growing season, data were also collected with a SPAD meter, hand-held Greenseeker, and Greenindex+ app. The OptRx reading didn’t show any significant differences between the N treatments and varieties during early and mid-season (48 and 53 DAP). But later in the growing season (87 DAP), the treatments such as 84 kg/ha at emergence, 28 kg/ha at emergence plus 28 kg/ha at R2-3, and 56 kg/ha at emergence ESN (Environmentally smart nitrogen) exhibited significantly higher VI compared to other N treatments. Also the varieties 6088 and 12R06 showed significantly higher VI than other varieties.  For the last date (87 DAP) of data collection, none of the other sensors except OptRx showed any significant difference between the treatments and varieties. Collecting subsequent years of data will be necessary to confirm the response of OptRx sensor to N application in different varieties of soybeans.