Extensive measurements have been made of atmospheric P concentrations and deposition rates in marine and remote continental areas. These data, when combined with other published data on P deposition rates over the continents, have enabled the estimation of the atmospheric burden the sources, the sinks, and the transfer rates of P through the atmosphere. We estimate that the total atmospheric burden of P is ~ 2.8 ×10 10g 90% of which is over the continents. Deposition rates are calculated to be ~320 ×10 10g yr -1 of P onto the continents and ~140 ×10 10g yr -1 onto the surface of the ocean. Major sources of particulate P in the atmosphere are estimated to be: (1) soil particles containing both naturally occurring and fertilizer derived P, ~400 ×10 10g yr -1;(2) P on sea-salt particles, ~ 33 ×10 10g yr -1 (3) P from industrial sources. ~26 ×10 10g yr -1. The major sources of industrial P emissions are the phosphate industry, ~16 ×10 10 g yr -1 and stationary combustion sources, ~ 5.7 ×10 10g yr -1. A net flux of ~100 ×10 10g yr -1 of P is transported from the continents to the oceans through the atmosphere. Almost 50% of this transport is due to the flux of dust from the Sahara desert to the North Atlantic between 15° and 25°N. The input of P which is easily soluble in sea-water is estimated to be 22 ×10 10g yr -1. This value is about 10% of the input of dissolved P to the oceans by rivers.