Spatial variations of heterotrophic bacterial production and phytoplankton primary production were investigated across South East Pacific Ocean (–141° W, –8° S to –72° W, –35° S) in November–December 2004. Bacterial production (³H leucine incorporation) integrated over the euphotic zone encompassed a wide range of values, from 43 mg C m^-2 d^-1 in the hyper-oligotrophic South Pacific Gyre to 392 mg C m^-2 d^-1 in the upwelling off Chile. Within the gyre (120° W, 22° S) records of low phytoplankton biomass (7 mg TChl a m^-2) were obtained and in situ ¹⁴C based particulate primary production rates were as low as 153 mg C m^-2 d^-1, thus equal to the value considered as a limit for primary production under strong oligotrophic conditions. In the South Pacific gyre average rates of ³H leucine incorporation rates, and leucine incorporation rates per cell (5–21 pmol L^-1 h^-1 and 15–56×10^-21 mol cell^-1 h^-1, respectively), were in the same range as those reported for other oligotrophic sub tropical and temperate waters. Rates of dark community respiration, determined at selected stations across the transect varied in a narrow range (42–97 mmol O₂ m^-2 d^-1), except for one station in the upwelling off Chile (245 mmol O₂ m^-2 d^-1). Bacterial growth efficiencies varied between 5 and 38% and bacterial carbon demand largely exceeded ¹⁴C particulate primary production across the South Pacific Ocean. Net community production also revealed negative values in the South Pacific Gyre (–13±20 to –37±40 mmol O₂ m^-2 d^-1). Such imbalances being impossible in this area far from any external input, we discuss the techniques involved for determining the coupling between primary production and bacterial heterotrophic production.