Hibernating mammals undergo a dramatic drop in temperature and blood flow during torpor and must suppress hemostasis to avoid stasis blood clotting. In addition, cold storage of most mammalian platelets induces cold storage lesions, resulting in rapid clearance following transfusion. 13-lined ground squirrels (Ictidomys tridecemlineatus) provide a model to study hemostasis and cold storage of platelets during hibernation because, even with a body temperature of 4-8C, their platelets are resistant to cold storage lesions. We quantified and systematically compared proteomes of platelets collected from ground squirrels at summer (activity), fall (entrance), and winter (topor) to elucidate how molecular-level changes in platelets may support hemostatic adaptations in torpor. Platelets were isolated from squirrel blood collected in June, October, and January. Platelet lysates from each animal were digested with trypsin prior to 11-plex tandem mass tag (TMT) labeling, followed by LC-MS/MS analysis for relative protein quantification. We found over 700 platelet proteins with significant changes over the course of entrance, torpor, and activity – including systems of proteins regulating translation, platelet degranulation, metabolism, complement, and coagulation cascades. We also noted species specific differences in hemostatic, secretory, and inflammatory regulators in ground squirrel platelets relative to human platelets. In addition to providing the first ever proteomic characterization of platelets from hibernating animals, our results support a model whereby systematic changes in metabolic, hemostatic, and other proteins support physiological adaptations in torpor. In addition, our results could translate into better methods to cold store human platelets, increasing their supply and quality for transfusions.