Despite many advances in chemotherapy and other medical techniques, patients with cancer often develop local recurrence or metastatic spread. Recent advances in molecular biology and tumor immunology have led to the design of many new anti-tumor vaccines. Such approaches are now using recombinant viruses to treat different types of cancer. From these new developments, innovative fields are emerging: vaccine virotherapy, viral immunotherapy, oncolytic virotherapy and drug virotherapy. Many viruses are currently exploited as recombinant vectors and each offers natural or synthetic characteristics that may provide unique means to treat cancer. Poxviruses are large double stranded DNA viruses that offer many advantageous characteristics as recombinant vectors. Poxvirus-based vectors offer essentially unlimited possibilities for genetic manipulation due to the large size of their DNA and high degree of safety. Vaccinia virus, the prototype virus of the Orthopoxvirus genus that was extensively used to eradicate Smallpox, and other poxviruses are now being considered and used for the treatment of cancer. This review will cover their utilization as anti-cancer therapeutics by describing recent patents (2000-2005).