Seven cases of the most severe form of tuberculous meningitis, in which a midbrain syndrome developed, are reported. Three different types of progress were observed. Exudative inflammation and cerebral edema dominated in the first group, causing the rapid development of the acute midbrain syndrome, which may turn into a bulbar syndrome. In the second group the development of the midbrain was delayed and an apallic syndrome followed. The morphological examination disclosed local diencephalic and midbrain lesions caused by herniation and specific vasculitis and vascular compression. The third group showed disintegration of cortical function as a result of parenchymal lesions, apart from local midbrain symptoms which never fully intensified into the midbrain syndrome. Observation of the progress of the disease proved that late diagnosis and delayed therapy were decisive in cases of the most severe form of tuberculous meningitis.