Positive and negative syndromes were studied in relation to demographic, historical, genealogical, clinical, psychometric, extrapyramidal, and follow-up measures of 101 chronic schizophrenic patients. The criterion scales proved to be reliable, normally distributed, and strongly correlated with general psychopathology, but otherwise inversely related to one another. Multiple regression analysis identified sets of 4-6 independent variables that explained 74%-81% of the scales' variance. A positive syndrome was associated chiefly with productive features, family history of sociopathy, more previous hospital admissions, and longer in-patient stay during the 30-month follow-up period. A negative syndrome correlated with deficits in cognitive, affective, social, and motor spheres, higher incidence of major psychiatric illness but less affective disorder among relatives, lower education, and greater cognitive developmental impairment. The results underscore the importance of genetic and biodevelopmental variables for understanding schizophrenic syndromes.