Cancer is not only a complex genetic disease, but also a disease of dysregulated bioenergetic metabolism. With improved technological advancements, the focus has shifted from changes in an individual biochemical pathway or metabolite toward changes in the context of the global network of metabolic pathways in a cell, tissue or organism. This global approach allows identifying changes in the pattern of metabolite expression in addition to changes in individual metabolite or pathway. Such a metabolomics approach promises a better understanding of tumor biology and identification of potential biomarkers with applications as diagnostic, prognostic and therapeutic targets. In this review, we discuss various techniques used in metabolomics and analysis of the data generated and its specific uses in cancer research including novel biomarker identification, development of more sensitive and specific diagnostic methods, monitoring of currently used cancer therapeutics to evaluate the prognostic outcome with a given therapy and evaluating novel therapeutic strategies.