The principal objective of cryosurgery is the localized destruction of the target tissue. However, in the course of destruction thereof, attention has been drawn to the contributory role of animmunologic response. Directed toward proteins (antigens) of the frozen tissue, the immune response following cryosurgery, ergo, cryostimulation, and the cryoimmune response, occurs locally and systemically, and is expressed by humoral- and cell-mediated immunity and associated cytokines. When considered in concert with its capability to elicit an immune response, cryosurgery provides a "double-edged sword" to our therapeutic armamentariurn and, thereby, a way to treat localized and metastatic cancer. One of several concerns toward achieving the successful cryoimmunologic augmentation of tumour destruction has been suggested to be related to the "cryosensitivity" of the subject. Cryosensitivity is currently defined by the immunogenicity of the target tissue (organ) and the immunecompetency of the subject. Continued developments in genetic engineering, which permit increased immunogenicity of tumours and enhancement and modulation of the immune response, provide unique opportunities to enhance the cryosensitivity of the subject and, thereby, the local and systemic cryodestruction of tumours. As we prepare to enter the next millennium, let us recognize that cryosurgery, in concert with its immunologic effects, is comparable and, in the case of metastatic disease, selectively advantageous to other modes of cancer therapy. Equally so, maximization of the synergist effect of cryosurgery and selective cytotoxic agents, i.e., cryochemotherapy, may prove useful.