Individual plants of peanut cultivar Florunner were evaluated over time for symptoms of tomato spotted wilt virus (TSWV) in field plots in 1988, 1989 and 1990. Time of symptom appearance was recorded for symptomatic plants. Seed yield was determined for individual symptomatic plants and apparently healthy check plants on adjacent rows. Across all times of appearance of symptoms, number of seed produced, mean weight per seed and total seed yield were lower for symptomatic plants than for healthy plants in all three years. In 1989 and 1990, linear regression indicated that both number of seed and seed yield per infected plant increased with time from planting until TSWV symptom expression. Mean seed weight also increased with time from planting until symptom expression in 1990, although this increase was small, but not in 1989. Among symptomatic plants, number of seed produced was more strongly correlated with seed yield than was average weight per individual seed.