The construct validity and extended stability of positive and negative syndromes were studied via multidimensional cross-sectional assessment of 134 schizophrenics in the acute, chronic, and long-term chronic stages. For all groups the syndromes were internally reliable, not significantly intercorrelated, and of similar severity. The syndromal correlates with clinical, motor, historical, and genealogical dimensions, however, differed as a function of chronicity. In acute schizophrenics, a negative syndrome was associated with clinical and genealogical indicators of good prognosis, whereas the converse obtained for a positive syndrome in the acute stage and a negative syndrome in the chronic stage. The relationship of education, marital status, and attention disorder to the positive-negative distinction also varied according to length of illness. Its meaning, therefore, appeared phase-specific and subject to evolution, obviating generalizations across all phases. Implications for theory, prognosis, current research, and future study are presented.