Progressive multifocal leucoencephalopathy (PML) is a progressive demyelinating condition resulting from infection with the John Cunningham virus and precipitated by immunocompromised states. The HIV pandemic, especially in sub-Saharan Africa, has resulted in an increase in the number of patients presenting with PML. Imaging plays an important role in diagnosis and the distribution of the disease is predominantly supratentorial. Isolated posterior fossa involvement is a rare finding with very few cases described in the literature. We present the largest case series of patients described in the literature, with isolated posterior fossa involvement of PML, in HIV-positive patients.