Disposal in 4- to 5-km-deep boreholes offers a safe, secure, environmentally sound, and potentially economic solution for high-level radioactive wastes, including spent fuel and fissile materials. Three versions of such disposals are under investigation: two variants of low-temperature disposal for low-heat-generating wastes and a high-temperature one for wastes generating sufficient heat to partly melt the host rock. A numerical model for the conductive transfer of heat is used to calculate the spatial and temporal distribution of temperature in and around these disposals. Sample solutions are given for two cases of each of the disposal versions, and the outcomes are discussed in the context of their significance for the safety and viability of the disposal. It is concluded that one or other of the three versions of deep borehole disposal could accommodate almost any type of high-level waste.