The ability of three insulated coolboxes recommended for vaccine transport to maintain vaccines below 10°C was evaluated. Studies using coolboxes and ice packs both precooled to 5°C indicated that the Giostyle Portable and Vaccine Carrier coolboxes were able to maintain loads below 10°C for periods up to two to four hours. Ice packs precooled to ‐20°C caused freezing of some vaccines in a load and should only be used if sufficient insulation is provided to separate the vaccines from the ice pack surfaces. The smaller Mailbox, with a lid‐positioned ice pack precooled to ‐20°C, maintained loads below 10°C for up t