The application of non-destructive pecan quality assessment would allow reliable quality checks of pecan batches. This research analyzed pecan samples using electromagnetic waves in the radio/microwave range from 100 MHz to 2.5 GHz with an open air transmission-type measurement device. Samples of the Maramec, Kanza, Pawnee, and Giles pecan cultivars were analyzed for the signal attenuation and phase shift using a network analyzer. Samples of each cultivar varied in both overall quality and moisture content. Several physical quality parameters of each sample were also measured. Measures of quality were correlated with the signal attenuation and phase shift values at 101 measured frequencies. Results suggest there is a linear correlation between both total kernel mass and edible kernel mass with both signal attenuation and phase shift measurements in the 400 to 500 MHz and 1.00 to 1.10 GHz ranges. Results can be applied to design an automatic pecan grading machine.