Since November 2015, Puerto Rico has reported active mosquito-borne transmission of Zika virus. Because of the potential for Zika virus to be transmitted through transfusion of blood components, and because a high percentage of persons infected with Zika virus are asymptomatic, the Food and Drug Administration (FDA) recommended that blood collections cease in areas of the United States affected by active vector-borne transmission of Zika virus until laboratory screening of blood donations or pathogen reduction technology (PRT) for treatment of blood components can be implemented. To inform efforts to maintain the safety and availability of the blood supply in Puerto Rico, CDC, in collaboration with the Puerto Rico Department of Health, conducted a rapid assessment of blood collection and use on the island. A total of 139,369 allogeneic red blood cell (RBC) units, 45,243 platelet units, and 56,466 plasma units were collected in or imported to Puerto Rico during 2015, and 135,966 allogeneic RBC units, 13,526 therapeutic platelet units, and 25,775 plasma units were transfused. Because of the potential for local Zika virus transmission in areas with a competent mosquito vector, other areas of the United States should develop plans to ensure local blood safety and adequacy. Blood collection organizations and public health agencies should collaborate to maintain the safety and availability of local blood supplies in accordance with FDA guidance.