The unique trait of the International Phosphorus Workshops (IPW) is the combination of terrestrial and aquatic ecosystems. The IPW’s arose from the understanding that eutrophication of waters is related to phosphorus management on land, including rural and urban areas, and that combating any phosphorus related problems requires the proper understanding of biogeochemical mechanisms and processes underlying the terrestrial-aquatic phosphorus continuum. Because the inefficient and unsustainable use of phosphorus in our societies is intimately linked to the dissipation of phosphorus into the environment, the IPW’s are also conferences on sustainable phosphorus use, including reuse of societal waste phosphorus, and efficient phosphorus use in crop and livestock production.