Gene therapy for haemophilia A would represent a significant improvement over the current treatment by providing prophylactic expression of FVIII and correction of the coagulation defect. Furthermore, a gene therapy protocol allowing simple, infrequent vector administration may extend haemophilia treatment to remote locations world-wide that currently lack access to FVIII replacement therapy. Within the last half decade, significant progress has been made on the development of gene therapy for the treatment of haemophilia A. Recent achievements include high level clotting factor expression in mice, dogs, and monkeys as well as phenotypic correction in haemophiliac mice and dogs. With the efforts that are currently directed toward the improvement of gene transfer vectors and the development of technologies to enable sustained clotting factor expression, gene therapy for haemophilia A will ultimately become a reality.