Results of this study, which included analyses of sequences for six gene regions and a large collection of isolates, confirmed the previous findings of de Beer et al.(2014) that the important root pathogen T. basicola is unrelated to species of Thielaviopsis in the Ceratocystidaceae. This provided adequate support for the establishment of a new genus for these isolates, and this study consequently introduces Berkeleyomyces for them. Furthermore, a relatively large global collection of isolates of T. basicola was shown to represent two distinct phylogenetic lineages. Based on a decision relating to the geographical occurrence of the fungus first described by Berkeley & Broome (1850), one of these taxa represents T. basicola sensu stricto. It is now treated as B. basicola and a reference specimen has been assigned for it (CBS 142796). The lineage accommodating the remaining isolates has been described as the new species B. rouxiae.