For over 2 years, we have had access to latest generation apparatus and software for planning and stereotactic treatment as well as for x-rays treatment. Until now, we have carried out over 100 procedures. These included 52 stereotactic biopsies of neoplasms, some of them located within the structures of the posterior fossa. In this report, we have discussed the possibilities and effectiveness of diagnosis and treatment of tumours located in different structures, including posterior cave. In the study, we used stereotactic methods. We have described biopsies of the following tumours: cerebellar hemisphere tumour (diagnosed as "metastatic atypic planoepitheliale carcinoma" in a patient with coexisting orbit lymphoma), a bifocal lesion (located in cerebellar hemisphere and cerebellar peduncle, diagnosed as pilocytic astrocytoma of WHO malignancy grade II/III), and lesion (located in the pons, diagnosed as pilocytic astrocytoma WHO grade II).