Abstract: Verticillium dahliae and Verticillium albo-atrum have been isolated from tomato cultivars possessing the Ve gene in many greenhouses in the Chott-Mariem region. Two isolates of Verticillium, one from each species, were examined for their mycelial growth at different incubation temperatures and their pathogenicity to three tomato cultivars. Seedlings at the three leaf stage were root-dipped in a conidial suspension (107 conidia mL-1) and maintained in two glasshouse cells at 17-21°C and 21-30°C. Disease severity was assessed through the index of leaf damage calculated 60 days after inoculation, at each temperature range. Growth test showed that V. albo-trum isolate as well as V. dahliae, were able to grow from 10 to 30 C. The three tomato cultivars exhibited typical Verticillium symptoms. The index of leaf damage differs significantly depending on cultivars, isolates and temperature ranges. V. albo-atrum was most virulent at 17-21°C; however, V. dahliae was more virulent at 21-30°C, despite the presence of the Ve-gene. These results confirmed the first report in Tunisia of a new pathotype of V. albo-atrum able to grow at 30°C and to infect cultivars having the Ve gene.