Based on water mass analysis, the Weddell Sea in the Atlantic sector was identified as the major source for Southern Ocean bottom water. Recent observations, and tracer analysis and modeling indicate that the Indian-Pacific sector might be the location of additional bottom water sources similar in magnitude as their Atlantic counterpart. Numerical model results presented here suggest that the Atlantic and Indian-Pacific contributions to Southern Ocean bottom water are roughly equal but for waters of different density. The observationally derived formation rate of dense Antarctic Bottom Water of the order of 10 Sv (1 Sv=106 m3 s-1) is confirmed by the model results but doubles if the lighter component of the Indian-Pacific sector is included. This result suggests that southern and northern hemisphere sources are equal contributors to the ventilation of the deep world ocean. ¿ 2001 American Geophysical Union