Tomato spotted wilt virus (TSWV) infections cause significant economic losses in the commercial culture of tomato (Lycopersicon esculentum). Culture practices have only been marginally effective in controlling TSWV. The ultimate way to minimize losses caused by TSWV is resistant varieties. These can be obtained by introgression of natural sources of resistance from wild relatives or by expressing viral sequences in transgenic tomato plants. We report high levels of resistance to TSWV obtained in an inbred tomato line, transformed with a DNA construct comprising the TSWV nucleoprotein (NP) gene. The high levels of resistance were maintained in hybrids derived from the parental transgenic tomato lines. Moreover, the transgenic hybrids remained completely free of TSWV symptoms in field trials under high virus pressure.