Phosphate is an essential element for plants and is involved in the composition of sugar phosphates, nucleic acids, membrane lipids, and energy metabolism via the generation of ATP. Crop farming requires the application of large amounts of phosphate fertilizer, but the fossilized rock deposits used as a commercial source of phosphate fertilizer are a nonrenewable resource that is predicted to reach a peak within the next century and drive plant production costs up as the global demand for food increases. Recent progress in the identification of key molecular regulators of the plant response to phosphate deprivation has highlighted differences in the response of the model plant Arabidopsis compared to economically important crops. This review focuses on the potential of proteomics to unravel the common and specific biochemical changes that contribute to phosphate use efficiency in cultivars of rice, maize, and oilseed rape. Proteome studies reveal a wide scope of species-specific metabolic strategies that lead to changes in root morphology and metabolism, driven by secretion of specific proteins and alteration of energy metabolism, carbon, and nitrogen assimilation inside the root cells. Understanding of the mechanisms underlying plant phosphate use efficiency in crops is critical for developing sustainable agriculture practices.