Accessions of Lycopersicon cheesmanii, L. chmielewskii, L. esculentum var. cerasiforme, L.hirsutum, L. parviflorum, L. peruvianum, L. pennellii, L. pimpinellifolium, and three interspecific hybrids of L. peruvianum with L. esculentum, were screened for resistance to the false root-knot nematode (Nacobbus aberrans) in greenhouse tests. Variability in nematode reproduction levels was observed within L. chmielewskii accessions LA 2695 and LA 2663 in initial tests with N. aberrans from Argentina; however, interspecific hybrids of L. esculentum cv. UC-82 × L. chmielewskii LA 2695, L. esculentum cv. UC-82 × L. chmielewskii LA 2663, and all the parent plants were susceptible in subsequent tests to the isolate of N. aberrans from Argentina and to an isolate from Mexico. The interspecific hybrids that possess the gene Mi and additional novel resistance to Meloidogyne spp. (root-knot nematodes) and all other exotic tomato accessions tested were susceptible to N. aberrans in our tests. Thus, we have been unable to identify or confirm resistance to two N. aberrans isolates in a range of Lycopersicon germ plasm accessions, including those that possess genes for resistance to root-knot nematodes.