There is a high prevalence of eye movement dysfunction (EMD) in persons with schizophrenia and their first-degree relatives. Studies addressing the prevalence, stability, familial transmission, and psychological correlates of EMD in persons from both psychiatric and general populations offer suggestive evidence that this abnormality may serve as a biological marker for schizophrenia. Although these findings are promising, their significance for elucidating the diagnostic bandwidth, pathophysiology, and genetics of this disorder remains to be determined. More precise characterization of ocular motility, perhaps when used in conjunction with global measures of pursuit adequacy, may be essential for clarifying the pathophysiological and genetic significance of EMD for schizophrenia. Recent research efforts are beginning to identify particular abnormalities that could serve as more specific biological markers for schizophrenia.