This paper studies the phosphate uptake by pure cultures of Aeromonas hydrophila, Klebsiella oxytoca, Agrobacterium tumefaciens, and Aquaspirillum dispar in the presence of both nitrate and oxygen. It is shown that species were able to respire both electron acceptors for phosphate accumulation. A. tumefaciens and A. dispar accumulated overall phosphate both in oxic and anoxic culture conditions, whereas A. hydrophila and K. oxytoca eliminated overall phosphate only in oxic conditions. A. dispar was able to remove phosphate by reducing oxygen and nitrate simultaneously with the production of dinitrogen gas. The anoxic denitrification observed in the cultures of adapted and nonadapted cells to nitrate showed that only A. dispar have a denitrification rate superior when the cells were adapted to nitrate.