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