Although platelets are the smallest cells in the blood, they are implied in various processes ranging from immunology and oncology to thrombosis and hemostasis. Many large-scale screening programmes, genome-wide association and '-omics' studies have generated lists of genes and loci that are likely involved in the formation or physiology of platelets under normal and pathological conditions. This creates an increasing demand for new and improved model systems that allow functional assessment of the corresponding gene products in vivo. Such animal models not only render invaluable insight in the platelet biology, but in addition, provide improved test systems for the validation of newly developed antithrombotics. This review summarises the most important models to generate transgenic platelets and to study their influence on platelet physiology in vivo. We will hereby focus on the zebrafish morpholino oligonucleotide technology, the (platelet-specific) knock-out mouse and the transplantation of genetically modified human or murine platelet progenitor cells in myelo-conditioned mice. The various strengths and pitfalls of these animal models are illustrated by recent examples from the platelet field. Finally we will highlight the latest developments in genetic engineering techniques and their possible application in platelet research.