As an overview provided to the South American Workshop on Marine Biodiversity, this article presents the unique collaborative approach of the Census of Marine Life (CoML) to increasing our knowledge of the abundance, distribution and diversity of marine life throughout the world's oceans. Five elements comprise the foundation of the research program, providing information and methods useful for enhancing our understanding of marine biodiversity, both historically and today, and making sound predictions of biological diversity in the future. (1) A series of initial field projects will demonstrate techniques or technologies to be applied to future studies. Some of these will test new technologies in well-known areas of the ocean, but most will take place in poorly known regions where both new and existing methods of surveying marine life will yield new information. (2) The Ocean Biogeographic Information System will make CoML and independent biological data accessible by serving as a single entry point to a distributed federation of databases. It will also provide tools for all users to create visualizations of the distribution and abundance of organisms together with environmental parameters in three dimensions. (3) Through the History of Marine Animal Populations, the historical component of the CoML, biologists and marine historians will mine and analyze historical records dating before human impact on the ocean became significant. (4) Exploring and documenting the multitude of ocean life accessible today requires advanced technology, and the CoML is working with the Scientific Committee on Oceanic Research Working Group on New Technologies for Observing Marine Life to move recent technological advances for observing marine life into the field. (5) The Future of Marine Animal Populations program will demonstrate and develop modeling approaches to hindcasting and forecasting changes in global biodiversity in response to fishing, pollution, and climate change.