BACKGROUND Steele-Richardson-Olszewski syndrome (SROS), which is also known as supranuclear palsy, is a neurodegenerative disorder and belongs to the atypical Parkinsonian syndrome family. Its typical symptoms consist of the triad vertical gaze palsy, slowing or absence of vertical saccades and a recent history of postural instability with otherwise unexplained falls. The reason for neurodegeneration in SROS is a genetically determined structural abnormality of the intracellular tau protein. Unless the expression of abnormal tau protein can be stopped by medication, there is no cure for SROS. METHODS Within the past 2 years, the results of neuro-ophthalmological and strabismological examinations in our department have lead to the diagnosis of SROS in 2 patients. RESULTS In patient #1, a 64-year-old man with an exophoria of 1 degree at far and near gaze, upgaze was limited to 15 degrees. Neither horizontal nor vertical saccades could be performed. No optokinetic nystagm response could be obtained in either direction. Additionally, the patient showed a staring facial expression, a slowing down in speech velocity and body movements and a postural rigidity. Patient #2 is a 67-year-old woman in whom the cover test revealed 4 degrees of esophoria at far and 4 degrees of exophoria at near gaze. Upgaze was limited to 10 15 degrees in both eyes. Saccades were slowed down in horizontal and vertical directions. Smooth pursuit movements were interrupted by spontaneous saccadic oscillations. In addition, the patient complained of a history of frequent falls and difficulties in writing and verbal articulation. CONCLUSIONS In both patients the clinical findings pointed to the diagnosis of probable SROS. A definitive diagnosis requires the histological proof of neurofibrillary degeneration with neuropil threads in a characteristic distribution in the brainstem and in the basal ganglia. Due to the similarity of symptoms to those of Parkinson's disease and atypical Parkinsonian syndromes, SROS may be misdiagnosed as such and presumably the true prevalence of SROS lies far above today's estimations.