Primary central nervous system (CNS) lymphoma appears to be on the increase. This increase is real rather than due to changes in nosology, physician awareness or increase in high-risk groups. Diagnostic guidelines appear to be well defined and widely accepted. We report 9 cases of primary CNS lymphoma seen at our institution over a 5-year period. The clinical presentation was variable, but consisted mostly of headache, motor dysfunction, and memory and behavioural disturbance. Surgery is of value for diagnosis. In general, surgical decompression is not recommended. Glucocorticoids and radiotherapy appear effective in the short term. The role of chemotherapy is uncertain.