Monitoring intracranial pressure (ICP) is an important element of neurosurgical critical care that is used primarily as an indicator of adequate cerebral perfusion. Such monitoring is usually done with intraparenchymal, subdural or intraventricular pressure sensor connected to a pressure transducer system. In the past, multiple studies have shown that there are certain pressure gradients between various intracranial compartments, especially if there is some focal intracranial pathological process. Several clinical and laboratory studies measured ICP inside the posterior fossa by placing the sensor into the cisterna magna or the cerebellopontine angle. None of them, however, monitored direct intraparenchymal pressure in the posterior fossa. Such measurement may be a more sensitive way to assess focal swelling, ischemia and tissue perfusion in the posterior fossa structures. We simultaneously monitored supratentorial ICP using an external ventricular drain placed in the lateral ventricle and infratentorial ICP with an intraparenchymal sensor inserted into the cerebellum. We subsequently analyzed data from five patients with different posterior fossa pathology each of which had simultaneous supra- and infratentorial ICP recordings for up to five days. We found difference in ICP between the infratentorial and supratentorial compartments and this difference changed over time. In this article, we discuss feasibility and safety of simultaneous infra- and supratentorial ICP monitoring in patients with the posterior fossa pathology.