Employing a hydroxyapatite double-stranded (ds) DNA column for affinity chromatography, anti-ds-DNA antibodies were isolated from the sera of aging NZB/W mice. These antibodies were radiolabeled and injected intravenously into NZB/W mice at various ages. Significant deposition of radiolabeled antibodies were shown to occur in NZB/W mice 4 months of age and older. While the injected antibodies displayed heterogeneity in their isoelectric points (pI's), those antibodies which bound to the kidney were restricted to a more alkaline pI range. Glomerular cultures were prepared from NZB/W mice at various ages and incubated with radiolabeled anti-ds-DNA antibodies with restricted pI's. Antibodies having pI's between 7 and 9 bound in vitro to glomeruli obtained from 9-month-old NZB/W mice but not to glomeruli obtained from 2-month-old mice. In contrast, antibodies with pI's between 5 and 7 were unable to bind to glomeruli obtained from either age group. An exchange between free antibodies and antibodies bound to glomeruli was also demonstrated to occur in vitro. These findings suggest the presence of subpopulations of anti-ds-DNA antibodies which preferentially bind to glomeruli containing immune complexes.