Lipidomics is a new term to describe a scientific field that is a lot broader than lipidology, the science of lipids. Besides lipidology, lipidomics covers the lipid-metabolizing enzymes and lipid transporters, their genes and regulation; the quantitative determination of lipids in space and time, and the study of lipid function. Because lipidomics is concerned with all lipids and their enzymes and genes, it faces the formidable challenge to develop enabling technologies to comprehensively measure the expression, location, and regulation of lipids, enzymes, and genes in time, including high-throughput applications. The second challenge is to devise information technology that allows the construction of metabolic maps by browsing through connected databases containing the subsets of data in lipid structure, lipid metabolomics, proteomics, and genomics. In addition, to understand lipid function, on the one hand we need a broad range of imaging techniques to define where exactly the relevant events happen in the body, cells, and subcellular organelles; on the other hand, we need a thorough understanding of how lipids physically interact, especially with proteins. The final challenge is to apply this knowledge in the diagnosis, monitoring, and cure of lipid-related diseases.