The authors compares results of neuropsychological tests/Halstead-Reitan Neuropsychological Battery, Stroop test, Wechsler Memory Scale, Seashore Tonal Memory Test/with results of smooth pursuit eye movements in nine pairs of twins/5 monozygotic and 4 dizygotic pairs/. In all instances at least one twin suffered from schizophrenia. The majority of neuropsychological tests differentiated clearly schizophrenic and healthy twins. Of seven parameters of smooth pursuit eye movements big saccades differentiated significantly. The authors found also correlations between neuropsychological tests and smooth pursuit eye movements. Significant correlations pertained to motor velocity (correlation of the Oscillation test with big saccades and with small saccades), complex psychomotor abilities (correlation of the Tactual Performance Test-Localization with big saccades), general indicators of cerebral activity or neuropsychological performance (correlation of the Tonal Memory test with big saccades and correlation of the Rhythm test with the amplitude of the curve), memory (correlation of the memory quotient MQ and the Logical Memory sub-test with small saccades) and work performance during a perception or psychic load (correlation of Stroop sub-test with big saccades). The method of smooth pursuit eye movements is not time consuming and does not involve major demands on the patient's cooperation. On the other hand, neuropsychological tests have the advantage that they reveal the impact of possible pathological conditions of the brain on behaviour. On the whole the results support the hypothesis that in schizophrenic patients a disease with structural or functional abnormalities of the brain is involved.