Two important sources of C apsicum annuum (bell pepper) resistance were evaluated for their response to inoculation with two isolates of T obacco etch virus strain NW ( TEV ‐ NW , genus P otyvirus ). The resistant cultivars were CA 4 and D empsey, which contain the pvr1 and pvr1 2 resistance genes, respectively. TEV ‐ NW was maintained by mechanical passage in the susceptible pepper cultivar E arly C alwonder and N icotiana tabacum cv. K entucky 14. In initial experiments, the TEV ‐ NW isolate maintained in E arly C alwonder infected two of seven CA 4 plants; however, none of the CA 4 plants inoculated with the TEV ‐ NW isolate maintained in K entucky 14 were infected. The infected CA 4 plants had low virus titres in non‐inoculated leaves and did not develop visible symptoms. When the infected CA 4 plants were used as inoculum of additional CA 4 plants, all newly inoculated plants became infected, developed systemic symptoms and accumulated virus in non‐inoculated leaves more quickly than the originally infected CA 4 plants. This new NW isolate, referred to as NW ‐ CA 4, was shown to overcome the resistances expressed by both CA 4 ( pvr1 ) and D empsey ( pvr1 2 ). The potyviral VP g is believed to be the determinant for pvr1 and pvr1 2 resistance genes, both of which are e IF 4 E ‐encoding genes. The VP g amino acid sequence for NW ‐ CA 4 was determined and compared with that of NW isolates and different TEV strains. No amino acid variation was identified that explained the infectivity of NW ‐ CA 4 in CA 4 and D empsey plants.