The proteome of Giardia duodenalis has been under study for the last 25 years and has lead to the discovery of valuable information on the biology and variation of the parasite.Proteomic techniques, mainly SDS-PAGE and 2D-PAGE, have been used to investigate protein variation, cellular structure and host parasite interactions. This has allowed for the identification of assemblage and host specific proteins, structural proteins, proteins released by trophozoites upon exposure to host cell monolayers and immunoreactive proteins. These data are important in understanding the pathogenesis of G. duodenalis infections, as well as highlighting potential drug and vaccine targets. There is however a large amount of future work needed to fully understand the proteome of this parasite.