The Malagarasi ecosystem is the stronghold for Shoebill Balaeniceps rex in Tanzania and is believed to host the largest population of the species outside the Sudd in Sudan. However, attempts to establish population numbers in Malagarasi seem to have resulted in considerable over-estimations. A review of the literature and aerial counts in November 2001 by the authors suggest that the Malagarasi population might comprise 100 or a few hundred birds only. The aerial survey in 2001 also revealed that previous estimates of the extent of certain wetland habitats in Malagarasi have been significantly overestimated. The authors therefore support the upgrade of the conservation status of Shoebill from Near Threatened to Vulnerable, i.e. with a total population of less than 10,000 individuals. Shoebill has a limited range from southern Sudan to northern Zambia and from eastern DR Congo to western Tanzania, and the species is threatened at all its main localities e.g. the Sudd swamps, Malagarasi, Bangweulu and in Uganda. A design for future aerial surveys of Shoebill is proposed focusing on identifying core areas for the species and comprehensive counts.