Gravity and GPS measurement as well as accompanying ice thickness determinations were performed along a tractor traverse from Patriot Hills to the South Pole, covering a distance of more than 1100 km. Special considerations were necessary to reasonably calculate the drift of the gravimeter used. Bouguer and ice layer corrections were accomplished by two-dimensional model calculations. The resulting complete Bouguer anomaly oscillates around zero along the northern section of the profile and starts to decrease 200 to 300 km before entering the  East-Antarctic craton where it stabilizes at about -130 mGal. Isostatic modelling yields a positive residual anomaly of about 70 mGal over East-Antarctica which can be explained by additional masses in the crust, e.g. assuming an increased density in the lower crust. Alternative models which incorporate lighter sediments in West-Antarctica or which are isostatically unbalanced are possible.