This paper describes why petroleum engineering techniques are of importance and can be used for underground disposal of HLW (high-level radioactive waste). It is focused on rock salt as a geological host medium in combination with disposal of the HLW canisters in boreholes drilled from the surface. Both permanent disposal and disposal with the option to retrieve the waste are considered. The paper starts with a description of the disposal procedure. Next disposal in deep boreholes is treated. Then the possible use of deviated boreholes and of multiple boreholes is discussed. Also waste isolation aspects and the implications of the HLW heat generation are treated. It appears that the use of deep boreholes can be beneficial, and also that--to a certain extent--borehole deviation offers possibilities. The benefits of using multiple boreholes are questionable for permanent disposal, while this technique cannot be applied for retrievable disposal. For the use of casing material, the additional temperature rise due to the HLW heat generation must be taken into account.