Technical Abstract: Peanut (Arachis hypogaea L.) plants infected with Tomato spotted wilt virus (TSWV) can display a wide range of disease incidence and severity depending on the year and location. Diagnosis of TSWV infection can be accomplished using enzyme-linked immunosorbent assay (ELISA) or reverse transcription polymerase chain reaction (RT-PCR) but there has been no report of a direct comparison of the success of the two techniques in evaluating infection rates of field-grown peanut plants. We collected peanut roots from field grown plants, 76 in 2006 and 48 for 2007, and subjected these samples to both ELISA and RT-PCR to test for the presence of TSWV. Out of 124 samples, 50 (40%) vs. 57 (46%) of the samples were positive for TSWV infection by ELISA and RT-PCR respectively. However, statistical analysis showed no significant difference between testing results for TSWV infection between these two methods. This result supports the conclusion that ELISA and RT-PCR are comparable methods for detecting TSWV infection rates in field-grown peanut.