Schizophrenic disorders as well as neuroleptic treatment can affect locomotion. The study assessed the influence of neuroleptic treatment on human gait via ultrasonic topometric gait analysis. In a control sample the test system proved high test-retest-reliability. Spatial and temporal gait parameters were assessed in schizophrenic patients without neuroleptic treatment (n = 12) and under treatment with conventional neuroleptics (n = 14) and re-assessed after treatment change to the atypical neuroleptic olanzapine in a repeated measures design. After switch from conventional neuroleptics to olanzapine patients showed an increase of gait velocity (p < or = 0.01) and step length (p < or = 0.01) whereas the cadence remained stable. Significant differences between the untreated state and treatment with olanzapine were not detectable. We conclude that bipedal gait is affected by conventional neuroleptic treatment. The degree of impairment can be objectively measured by testing spatio-temporal and kinematic gait parameters via three-dimensional ultrasonic gait analysis.