Lithospheric xenoliths are a convenient and relatively cost efficient means of gaining an insight into the petrology of the deep earth. As such, they provide important information on lithospheric structure and processes and can be used to gauge thermal regime and possibly , the timing of events. Lithospheric xenoliths were collected in the 1989/90 and 1990/91 season from Marie Byrd Land, West ... Antarctica, including Mt Waesche, Mt Sidley, Mt Cumming, Mt Hampton and the USAS Escarpment (Mt Aldaz) in the Executive Committee Range and Mt Murphy in the Mount Murphy Volcanic Complex. Further samples were collected in the 1992/93 season from the McMurdo Volcanic Province at a number of localities on and adjacent to Ross Island (Hut Point Peninsula (Half Moon Crater, Sulphur Cones, Turtle Rock) and Cape Bird), Black Island and in the foothills of the Transantarctic Mountains (Foster Crater on the Koettlitz Glacier). The majority of the samples collected in the 1992/93 season supplemented a collection compiled from the 1982/83 and 1984/85 season. The xenoliths vary from texturally variable, spinel lherzolites and dunites representative of upper mantle assemblages to ultramafic Al-augite kaersutite bearing ultramafic rocks and plagioclase bearing ultramafic to mafic granulites thought to represent the transition zone between upper mantle and lower crust.