During the 6 year period from January 1980 to December 1985 44 patients with infection of the central nervous system by Gnathostoma spinigerum or Angiostrongylus cantonensis were admitted to the Division of Neurology, Ramathibodi Hospital, Bangkok, Thailand. In 16 patients the diagnosis could be confirmed serologically by means of ELISA techniques. In gnathostomiasis encephalitis, myelitis, radiculitis and subarachnoid haemorrhage formed the majority of clinical syndromes. Intracerebral haematoma and transitory obstructive hydrocephalus are described in this report as being caused by Gnathostoma spinigerum infection for the first time. In angiostronglyus infections the clinical syndrome of meningitis was predominant, but one patient, whose angiostrongyliasis was proved serologically, also showed bilateral paresis of abducens nerve. The main laboratory finding was eosinophilic pleocytosis in the CSF (greater than 10%) which in patients originating or returning from South-East-Asia, particularly Thailand, is highly suggestive of these parasitic infections. Increasing transcontinental travel, influx of refugees and those seeking asylum as well as importation of food from South East Asian countries demand greater awareness of these parasitic infections even in Central Europe.