The invention relates to stable formulations of antibodies against humanprogrammed death receptor PD- 1, or antigenbinding fragments thereof. In some embodiments the formulations of theinvention comprise between 5-200 mg/mL anti- PD-1 antibody,or antigen binding fragment thereof. The invention further provides methodsfor treating various cancers with stable formulations ofthe invention. In some embodiments of the methods of the invention, theformulations are administered to a subject by intravenousor subcutaneous administration.